Joomla - popular, award-winning CMS that will help you build powerful online applications.

Drupal - equipped with a powerful blend of features, rich set of modules, very popular.

e107 - totally customizable content management system written in PHP using MySQL database.

Plone - ready-to-run, easy to set up, extremely flexible, and ideal for project groups, communities, websites, extranets and intranets.

Zope - an open source application server for building content management systems, intranets, portals, and custom applications.

PHPnuke - established CMS featuring web-based administration, surveys, customizable blocks, modules and themes with multilanguage support.

Dotnetnuke - port of PHPNuke into Microsoft .NET platform.

Typo3 - flexible and extensible CMS with an accomplished set of ready-made interfaces, functions and modules.

PostNuke - fork of PHP-Nuke to make it more secure, stable, and able to work in high-volume environments with ease.

SyntaxCMS - simplify publishing , create and edit site content online, and approve it before publishing to the web.

jLibrary is a DMS (Document Management System), oriented for personal and enterprise use.

V2 CMS - simple CMS, easy to install and modify.

Website Baker - PHP-based CMS designed to make website creation easy.

Jahia - use the Jahia community edition for publishing, managing files, and workflow.

eZPublish - created by eZ Systems, which has a team of professional software developers responsible for creating and maintaining the CMS.

Magnolia - makes Enterprise Content Management simple by being user-friendly, battle-tested, enterprise-ready and open-source.

WebGUI - built to give average business users the ability to build and maintain complex web sites.

OpenCMS - helps content managers worldwide to create and maintain beautiful websites fast and efficiently.

PHP-Fusion - a lightweight, small and versatile CMS.

Collaborative Portal Server (CPS) - most complete platform for building Enterprise Content Management applications, built on top of the Zope application server.

SiteFrame™ - lightweight content-management system designed for the rapid deployment of community-based websites.

TribalCMS - includes multilanguage support, template architectures, AJAX User Interfaces and unique administration.

Xaraya - create sophisticated web applications; designers enjoy considerable flexibility.

Krang - designed to publish magazine websites.

MMBase - CMS with strong multi media features and advanced portal functionalities.

Pligg - based on Menéame (Spanish Digg clone), Pligg enables you to create Digg -like sites.

elevateIT - an extension of ZOPE/Plone server.

Cofax - manages your text and multimedia content, and simplifies the presentation of newspapers.

DBPrism - first open source CMS based on Oracle XMLDB repository.

Flux CMS - XML/XSLT based, easy to use, extensible and suitable for developers to fill specific needs.

Apache Lenya - Java/XML based CMS that comes with revision control, multi-site management, scheduling, and workflow.

Rubricks - CMS for Ruby on Rails fans, boasts simplicity and speed.

Silva - built on top of Zope, enables you to export to Word, stream media, store content as XML, and manage hierarchical and traditional websites.

YACS - build your online blogging communities.

Clever Copy - A scalable website portal and news posting system.

Fundanemt - focused on usability and aimed at small and medium sized websites.

Dragonfly CMS - feature-rich open source content management system, based on PHP-Nuke 6.

ContentNOW - simple to use, flexible, multilanguage, modular CMS.

Bitweaver - suitable for large-scale community websites and corporate applications.

Elxis CMS - professional free open source CMS released under the GNU/GPL license.

Etomite - allows you to remotely administer your website from anywhere.

fuzzylime - simple way for you to run your site and keep it up-to-date.

iGaming CMS - build your own gaming websites.

MODx - CMS that helps you take control of your online content.

PHP comasy - simple, multilingual and fast content management system.

Mambo - very well-known CMS. Can be used for everything from simple websites to complex corporate applications.

Jupiter - one of the most lightweight portal systems available.

Ovidentia - integrate an environment for publishing content on the www or a groupware portal.

Jaws - build your own modules on the powerful Jaws framework.

Geeklog - out of the box blog solution with support for comments, trackbacks, multiple syndication formats, and spam protection.

CMS Made Simple - make a home page for your family or your multinational corporation.

Eazy portal - solution allowing you to maintain your own online community.

Papoo - accessible content management system

phpWebSite - develop an interactive, community-driven website.

RunCms - portal system that includes most things a webmaster would expect from a CMS.

Exponent - allows site owners to easily create and manage dynamic websites without necessarily directly coding web pages, or managing site navigation.

SPIP - publishing system, use it freely for your own site, be it personal, co-operative, institutional or commercial.

Silverstripe - powerful enough for any website or intranet design and simple enough for anyone to use.

Pheap - created for folks who don’t like complex CMSs like Joomla and Drupal.

MDPro - an innovative and imaginative content management system.

TYPOlight webCMS - specializes in accessibility and uses XHTML and CSS to generate W3C/WAI compliant pages.

PlumeCMS - have multiple websites, multiple authors with different rights.

Xepient Open-Point - create a professional website quickly through the browser.

SlashCode - the original code for the Slashdot geek news service.

YaWPS - is a hybrid between a content management system and a web portal for medium or small-sized websites.

APC ActionApps - allow authorized users to easily update the content of their website.

Pagetool - suitable for people with limited technical skills to modify and contribute to an organization’s web site

OpenACS - toolkit for building scalable, community-oriented web applications.

ttCMS - build your community website with calendars, surveys, member management and authentication, file downloads, forum, articles, and announcements.

MySource - enables technically unskilled users to build and maintain their own web solutions.

Ariadne - web application server and content management system.

Mason CM - makes it easy to manage the workflow of information as it moves from staging to the live site.

Managee - comprehensive web based CMS.

ESY Web Builder - an intuitive content management system that allows non-technical people to create and manage websites and extranets.

PHProjekt - a groupware suite, for the coordination of group activities and to share information and documents via intranet and internet.

PROPS - extensible publishing system designed specifically for periodicals such as newspapers and magazines

Midgard CMS - internationalized set of tools for building web sites and networked applications.

Pivot - web-based tool to help you maintain dynamic sites, like weblogs or online journals.

Anteil - Cost effective open source solution for managing and improving customer relationships.

CitrusDB - CitrusDB is a PHP & MySQL based open source customer database solution.

CiviCRM - The world’s first downloadable constituent relationship management system; fund raising software that allows users to manage information about donors, volunteers etc.

Compiere - Offers integrated ERP and CRM suite that enables users to automate the financial, distribution and other needs of their businesses.

Daffodil CRM - Organized and effective way of managing cost-effective customer relationships.

Hipergate - Serving developers, consultants and enterprises to assist them in project management, sales force automation and customer relationship management.

IGSuite - A web-based integrated CRM suite that includes solutions like mailing lists, calendar, contact management and task lists.

Keen CRM/ERP - An advanced, feature packed, comprehensive customer relationship management solution for small companies.

Ohioedge CRM - Ohioedge CRM is an enterprise level open source CRM solution.

OpenCRM - OpenCRM is an open source CRM solution for tracking clients and project management.

OpenCRX - A cross platform professional CRM solution with bug tracking and activity management features.

SellWinCRM - An open source CRM project giving a high level of customization for customers.

SourceTap CRM - SourceTap CRM is a flexible sales force automation solution developed to meet the requirements of sales managers and representatives.

SugarCRM - An open source CRM solution allowing users to track opportunities and manage existing customers while keeping a check on other activities.

Turquoise CRM - Lightweight CRM software built over LAMP with Business Intelligence functionality.

Tustena CRM - Tustena is an enterprise level open source CRM solution written in C#.

vtiger CRM - Built over LAMP/WAMP, Vtiger provides excellent business enhancement utilities and is compatible with multiple platforms.

XRMS CRM - XRMS is an advanced level open source CRM solution that includes a Business Intelligence suite and advanced plugin architecture.

bbLean - A new version of Blackbox for Windows.

BlackBox For Windows - An alternative shell for Windows that is based stylistically on the Blackbox window manager for the X Window system.

Blueberry 3D-Desktop - Made using Delphi; its main objective is a 3D OPENGL engine in replacement of the Windows desktop.

CyGNOME - A nice tool which ports GNOME desktop to Windows.

DM2 - Provides useful enhancements for Windows in daily work like minimizing windows to floating icons, freeing the taskbar etc.

Geoshell - A shell replacement for Windows that replaces the standard desktop interface items like start menu, taskbar, system tray etc.

KDE-Cygwin - KDE’s port in Windows desktop environment.

LiteStep - A powerful Windows shell replacement under GPL and inspired by AfterStep.

SharpEnvironment - A tool that enables users to personalize every pixel of visible space and customize a single theme in multiple ways with real-time wallpaper effects, icon sets etc.

Virtual Dimension - A fast and fully featured virtual desktop manager that acts as an enhancement to the Windows manager.

xoblite / Blackbox for Windows - An advanced level Blackbox for Windows that is integrated with a system bar.

Columba - A java based email client featuring a user friendly graphical interface.

Daffodil Organizer - Highly flexible way to organize emails; includes import facility from Microsoft Outlook.

Evolution - More popularly billed as the Outlook of Linux , its calendar, address book and other features make it a good option as an email client.

ICEMail - Open source java client with support for the latest email standards.

Mahogany - Cross platform email client supporting UNIX and Win32 platforms.

Mutt - A small and powerful text based email client for UNIX operating systems.

Penelope - The open source version of Eudora currently under beta and planned for full release by this year.

Phoenix Mail - One of the older open source email clients developed using Borland Delphi.

Sylpheed-Claws - An open source email client with an interface similar to Outlook Express; works as an RSS feed reader too.

Thunderbird - A secure email client with several customization options to fit the user's needs.

Zimbra - Zimbra is currently one of the biggest names in open source, and is the future collaborating and messaging software. Now owned by Yahoo.

Alba Extractor - Alba Extractor is a useful utility for wrapping various mp3 files into one unit for ease of sharing on programs like NapShare etc.

Audacity - Audacity is an open source, cross platform audio editor and is a good solution for creating and editing podcasts.

Avidemux - A free video editor for tasks like cutting and filtering; has support for file types like AVI, DVD etc.

AviSynth - A powerful tool for editing and processing videos.

BonkEnc - A useful application for ripping CDs, encoding and converting audio files to various formats. Users can produce mp3, mp4, FLAC files to name a few.

CD-DA X-Tractor - An open-source CD ripper for 32-bit windows platforms that offers extremely high quality.

CDex - A popular open source digital audio CD extractor.

DivFix - DivFix is a utility for watching partially downloaded DivX movies.

DivXRepair - Based on the VirtualDub model, it cuts off the bad parts and re-assembles the AVI file.

Dr. DivX - The goal of Dr. DivX open source project is to create a portable application with the capability of transcoding many video formats.

DScaler - The DScaler project is an effort to receive top quality videos from Windows computers.

DVD2AVIdg/MPEG2DECdg Decoding Fix - An MPEG decoder suite used for decoding MPEG1 or MPEG2 streams from sources such as DVD VOBs.

DVDx - Popular DVD backup software that converts DVDx movies to high quality DVD movies.

FFmpeg - A complete recording, conversion and streaming solution for audio and video.

GiantDisc - GiantDisc is an open source software package designed to manage thousands of audio tracks.

GNUMP3d - Open source server for streaming mp3s and media.

Gordian Knot - Gordian Knot is an integrated Bit rate calculator package tool for Divx/XviD encoding.

GramoFile - A CD recording utility running on Linux and some other operating systems like UNIX. It enables users to put sounds from gramophone records on CD.

HGRip - A one click solution for converting DVD to XVID files.

JMAC - JMAC is an open source Java implementation library of Monkey’s Audio compression decoder.

LAME - LAME is an MP3 encoder.

Mixere - Mixere is a free, open-source application for mixing audio files. It runs on Windows NT/2000/XP, and supports WAV, AIFF, MP3, Ogg Vorbis, FLAC and Mod audio files.

MMConvert - A multimedia format converter useful for converting media files from one format like AVI/WMV to another format.

mpgtx - A command line MPEG audio/video toolbox useful for joining audio and video files which include MP3, MPEG1, MPEG2 etc.

Mp3splt - A terrific utility to split MP3 and Ogg files from anywhere without decoding.

Mp3Wrap - A useful alternative to wrap two or more mp3 files into a single large mp3 without the loss of file names and other information.

Musepack - A high quality audio compression format.

MusicBrainz Tagger - Provides a database to create a comprehensive music information site. It can be accessed via the client or the internet.

NanDub + BRC - NanDub+BRC includes a bitrate calculator and offers users several advantages as their need for opening separate pieces of software is eliminated.

Open Sound World - A scalable programming environment allowing musicians, researchers and sound engineers to process sound.

OptimFROG - OptimFROG is a zipping utility for audio compression programs; used to reduce the size of audio files.

ShrinkTo5 - A cross platform open source DVD copy engine; allows users to create copies.

SmartRipper - A useful utility for extracting DVD VOB files; loaded with nice features for splitting VOB files, angle processing etc.

Taksi - Taksi allows users to take screenshots and record videos of favorite games and 3D-graphics applications.

Virtual VCR - A compact video capture application designed to work with TV tuner and video capture cards.

WavPack - WavPack is a high quality audio compression format and provides lossless compression.

YAAI - One of the best tools to display information about AVI files; enables users to see data like framerate, used codes, author information etc.

ADempiere Bazaar - Adempiere is a community for open source developers contributing improvements of various applications like Compiere, Helpdesk and Supply Chain etc.

JERPA - JERPA is a Java based advanced level architecture model for ERP software.

JFire - An exchange platform including ERP, CRM and accounting written in Java.

Openbravo ERP - A web based ERP for small and medium enterprises; built on proven MVC architecture facilitating code maintenance and customization.

opentaps - An open source ERP and CRM suite including eCommerce, inventory, warehouse, ledger etc.

Postbooks - A fully integrated ERP solution for small and medium businesses; features a graphical client which runs on Linux, Mac and Windows.

Plazma - Plazma is a Java based ERP and CRM solution.

Sequoia Open Source ERP - The flexible ERP software from Sequoia brings advanced features and scalability for enterprise software along with low TCO.

Tiny ERP - Packed with features like GTK2 client, distributed server, dynamic GUI.

Value - Value is an open source ERP/CRM system and features modular capabilities along with seamless integration.

webERP - webERP is flexible integrated business management software that covers accounts receivable, accounts payable, inventory management and other accounting requirements.

Wyatt - Wyatt is a cross platform ERP package written in Java with J2EE compliance.

ABC - An enhanced client for the BitTorrent file sharing protocol.

Ares - A file sharing utility enabling users to share digital files like images, audio, video, software and documents.

Azureus - Java enabled BitTorrent protocol packed with special features for beginners and advanced users.

BT++ - An advanced version of the BitTorrent peer-to-peer file sharing protocol with cross-platform support; written in Python.

Cabos - Cabos has an intuitive user interface and is a Gnutella file sharing program based on Limewire.

CoreFTP - A FTP program that enables uploading/downloading/deletion of files and directories, integration with browser, file permission handling etc.

cURL - A command line utility allowing file transfer via FTP, LDAP etc. Users can also use the GET and PUT methods for file downloading and uploading.

DC++ - Windows based open source client for unrestricted file sharing over the internet.

eMule-Project.net - A reliable and trusted peer-to-peer file sharing application allowing users to connect from different clients.

FileZilla - FileZilla is a free, fast and reliable open source FTP solution for Windows.

Freenet Project - A free and secure decentralized network of information publishers and consumers.

FrostWire - A completely open source peer to peer client; features community chat room and iTunes integration.

Fugu - An open source graphical front end for secure file transfer; provides support for Mac operating system.

G3 Torrent - A BitTorent client written in Python.

Gnucleus - One of the oldest Windows based open source peer to peer file sharing clients related to Gnutella.

HeavyMole - An advanced level peer to peer file sharing application with features like distributed chat, filtering of answers and advanced query language.

iFTP - i.FTP is a Windows FTP client that comes with source code. There is also an earlier version for BeOS that works with portable media like USB keys.

JFtp - JFtp is a graphical Java network and file transfer client.

KazaaSearch - Search for music, software, images & video with this powerful peer to peer file sharing client.

KCeasy - The windows version of giFT filesharing system that also offers support for other filesharing networks.

Krimpy - An IRC based (internet relay chat) open source file sharing client enabling users to share music, pictures, videos and other files.

Lime Wire - A multi-platform Gnutella file sharing client enabling users to share their files, download MP3s and other audio files.

MLdonkey - 100% open source cross-platform P2P client running on Linux, UNIX, Windows and Mac.

MUTE - A secure, peer to peer file sharing network with easy search and download functionality.

MyNapster - Comes with connection capability to Gnutella for file sharing, IRC for chatting and supports resumption & multithreading of downloads.

NetMess - Has the ability to detect clones and work through HTTP proxy and firewalls.

Prozilla- An open source Linux download accelerator that provides download support via HTTP and FTP protocols.

Shareaza - A flexible file sharing system consolidating features from four different networks: EDonkey2000, Gnutella, BitTorrent, Gnutella2.

TAC2 - Expanded as Tango & Catch 2 (TAC2), works as a search engine independent client for searching on Linux and Windows.

TorrentSpy - Gives BitTorrent power-users all the information in one place along with real time ability to monitor the number of live users.

Waste - Secure collaboration tool allowing idea & data sharing between users through a chat interface.

WinSCP - Another open source SFTP & FTP client for Windows; provides safe file copying between local and remote computers.

XNap - Written in Java, XNap provides a plug-in enabled framework and client for P2P applications.

Ajax Image Editor - Open source image editor using PHP.

ArgoUML - ArgoUML is a popular open source UML modeling tool compatible with any Java platform.

Avidemux - A simple video editor with support for DVD/DivX conversion and editing.

Blender - 3D animation and modeling suite with various tools for modeling.

Bluefish - A powerful editor for programmers and web designers enabling them to write websites, scripts and programming code.

BRL-CAD - An open source CAD system centered on constructive solid geometry (CSG) modelling.

Cinelerra - A professional open source video editing tool with features for capturing, editing and compositing.

CinePaint - Professional graphical editing application targeted towards the movie industry.

Cornice - Cross platform image viewer initially developed for Linux; similar in functionality to ACDSee.

Dia - Open source drawing tool for UML diagrams, similar in functionality to ‘Visio’.

Flowchart Studio - Allows the user to draw a flowchart through graphical editor.

F-Spot - A feature rich personal photo management application for GNOME desktops.

Gaphor - Simple modeling environment that enables users to create intuitive UML diagrams for documentation purposes.

Gimp - The oldest, and most famous, open source graphic application with over 100 plug-ins and powerful paint tools.

Gimpshop - Gimpshop changes menus and dialogs in a manner similar to its competitor, Photoshop.

GQview - A lightweight image viewer with easy navigation, zoom and thumbnail preview features.

i.Mage - i.Mage is a handy graphics editor featuring easy pixel & image editing.

ImageMagick - Allows for the creation, editing and composition of bitmap images.

imgSeek - imgSeek is a photo management and viewing application with search support.

Imgv - An open source, feature rich image viewer providing support for a variety of image formats.

Inkscape - A fast visual web picture ripper, downloader and offline browser.

Jahshaka - Powerful open source movie editor with real time media playback and visual effects.

Karbon - Part of the open source KOffice suite, makes a great choice as a vector drawing application.

Kino - An open source non-linear video editor that comes with easy importing of DV video and provides video and audio transition effects.

khtml2png - A command line utility for creating PNG and JPEG images out of web pages.

Krita - An open source image editing and painting program with advanced features.

KToon - 2D animation toolkit with focus towards animation industry.

NVU - A complete cross platform web authoring system which makes it very simple to create web pages and manage a website without any technical expertise.

OpenLaszlo - An excellent development environment for web applications as it can generate Macromedia and AJAX files for webpage use.

Paint.NET - .NET based open source bitmap application with an intuitive user interface for drawing and editing.

Page Scavenger - A simple Windows application useful for downloading images from free hosting services via webpage links.

Pixie - Open source RenderMan renderer.

Potrace - An open source project useful for converting bitmap images to raster or vector drawings.

QCad Community Edition - A simple, easy to use open source 2D CAD application.

Quanta Plus - A feature rich web development environment.

Seashore - A basic open source image editor with simple functionality and features.

Scribus - Open source cross-platform desktop publishing application.

Skencil - A flexible open source, interactive vector drawing application for illustrations, diagrams and other purposes.

Synfig - An open source 2d vector animation program for artists to assist them with making cartoons.

UFRaw - Unidentified Flying Raw is an open source photo converter that can be used as a standalone application or as a plug-in.

VirtualDub - An open source video capture and processing utility with basic features.

Violet - Violet is an easy to learn and use open source UML editor.

Xara Xtreme - Powerful, general purpose graphics application for Linux and other UNIX platforms.

AlsaPlayer - AlsaPlayer is a new type of PCM player for Linux/Unix featuring fully pluggable framework for various media types.

Amarok - Audio player for Linux.

Cog - Quite often referred to as a potential iTunes alternative; an interesting open source audio player with support for various formats.

Coolplayer - A fast audio player for the Win32 environment.

Delphamp - Delphi based open source media player. Like a Winamp clone, also features support for Winamp skins.

DigitalDJ - DigitalDJ is a front-end MP3 player based on SQL. It can create playlists and manage CD databases in MP3 format.

Foobar2000 - Advanced level Windows based audio player with support for Unicode and popular audio formats.

Gamp - Gamp is a Gnome audio player written in C and includes support for MP3, Ogg, vorbis etc.

Grip - Grip is a CD-player and ripper for the Gnome desktop, and features an automated front end for MP3 encoders.

Guliverkli - Its interface is similar to Windows media player, however it also offers advanced features like switching of audio streams in mp4 files.

HelixPlayer - An open source media player for various operating systems like Linux, Solaris and Symbian.

Juice - Juice is a premier podcast receiver and allows users to capture and receive podcasts anytime.

Media Player Classic - An advanced version of Windows Media Player 6.4; offers features like real time zoom, support for AVI subtitles and support for QuickTime and Real video.

Mixxx - An open source DJ mixing tool, very useful for professional and amateur DJs.

Miro - The only video player which provides you with the option to download YouTube - videos, play video files and play live Internet TV.

MPlayer - Written in Python; one of the best media players under the GNU-GPL license.

MP3Gain - MP3Gain assists users by normalizing the volume of mp3 files; it also does statistical analysis to determine the loudness of a file to the human ear.

musikCube - MP3 player based on embedded SQL database engine and packed with innovative features.

NotifyCD - NotifyCD is a small system tray based CDDB supporting CD player for Windows 9x/NT/2000.

OggPlay - OggPlay is an open source audio player for smart phones.

Plainamp - Plainamp is an open source media player for Microsoft Windows.

SnackAmp - A music player running on multiple platforms; features a web server and powerful playlist.

Songbird - Songbird is a multi-utility open source application; acts as a desktop web player, a jukebox, and a web browser.

SysTrayPlay - Also known as STP, ths is a small MP3 player program with a grey button in the taskbar that occupies very little memory.

VLC media player - Highly portable cross platform multimedia player & streaming server with support for variety of audio and video formats.

Vorbis.com - Open source professional audio encoding and streaming technology.

XboxMediaPlayer - XboxMediaPlayer is an open source multimedia player from Microsoft useful for viewing various video/audio/picture files like VOB, AVI, MP3 etc.

xine - Xine is an open source multimedia player for playing CDs, DVDs and streaming multimedia over the internet.

Zinf - Powerful and effective audio player for Linux and Windows. Supports various file formats such as MP3, Ogg and WAV and also features a download manager and a music browser.

Adium - Mac OS X open source instant messaging client that aggregates the popular IM networks.

aMSN - MSN Messenger’s open source clone for Linux users.

Ayttm - Ayttm is an instant messaging client with all-in-one chat functionality for major instant messaging services.

Coccinella - A Jabber client with integrated whiteboard features; includes features like file transfer, multi-user chat etc.

Kopete - Part of KDE desktop; a wonderful instant messaging application with voice and video capabilities.

Gaim - A very flexible instant messaging application compatible with Linux and Windows offering support for AIM, ICQ, MSN, Yahoo and others.

Ineen - Ineen is a feature loaded open source audio and video conferencing desktop tool.

IRSIM - Uses PHP and mySQL and provides interaction with multiple messaging clients.

Java Jabber Server - A nice open source Java implementation of Jabber instant messenger.

Kopete - Kopete is a flexible instant messenger and multi protocol system with support for AIM, Yahoo, IRC and MSN.

Licq - A C++ based multi-threaded ICQ clone; uses an extensive plug-in system.

MIMP - Mobile version of IMP; functionality includes mailbox viewing, message viewing, deletion or composition of new messages.

Miranda IM - Fast and handy multi-protocol messenger for Windows.

Openfire & Spark - Real time cross-platform IM client and server based on Jabber protocol.

Pidgin Pidgin - Covers multiple protocols including AIM, ICQ, MSN, IRC, Jabber etc.

PlanetaMessenger.org - Java based open source instant messenger offering plug-in support for various IM networks.

Psi-im - An open source instant messaging client developed for Jabber. Has communication capabilities with AIM, MSN and ICQ etc.

SIM-IM (SIM Instant Messenger) - Free software package providing plug-in based messaging with support for various protocols.

Spark - Open source instant messenger with integrated support for group chat, telephony and security.

TjK - A portal based open source version of AOL Instant Messenger, originally developed for UNIX users.

Tkabber - Open source client for Jabber instant messaging and works on many platforms e.g. Linux, Windows and Mac etc.

WengoPhone - WengoPhone is a popular VOIP soft-phone client for making free PC-to-PC calls over the internet.

XChat - An IRC chat client for both Windows and Linux.

Yafumato Web Messenger - A web-based open source client allowing users to connect to AIM, Gtalk , MSN and Yahoo.

CC PDF Converter - Enables users to convert Word, Excel, IE and any other file formats to PDF.

Evince - Evince is a document viewer with support for multiple document formats including PDF.

Jarnal - Jarnal is an open-source application enabling annotation of a document.

okular - A universal document viewer based on KPDF for KDE.

PDFCreator - Create PDF files from just about any Windows utility.

PDF Download - A Firefox extension for improving your surfing experience. A click on a PDF file link enables you to view it inside or outside Firefox.

Pdftk - Pdftk is a command line utility allowing users to merge PDF documents, split PDF documents and do many other things.

qvPDF - Windows based PDF creator implemented as a printer driver.

Sumatra PDF - A simple and fast application to view PDF files.

Xpdf - An open source PDF viewer for the UNIX operating system. Also works under Windows as a command line tool.

Aethera - Aethera is a PIM application with communication features like send/receive email, send/receive tasks and appointment requests etc.

Chandler - Turns your inbox into a task list.

KAddressBook - An address book application for the K Desktop environment.

Kontact - Supports news, email, calendars, to-do list; a personal information manager for KDE.

KOrganizer - A personal organizer of the KDE desktop environment; has the ability to manage calendars and to do list.

Nag - Nag is a task list manager for multiple users and allows them to create many task lists which can be shared between users and groups.

OneOrZero - Easy to customize cross platform, enterprise level task management and help desk solution.

OpenSync - Open source synchronization framework for managing PIM data such as contacts, calendar, tasks and notes.

PTM - An open source time tracking tool.

Task Blocks - A simple task scheduling application to ensure that user tasks do not overlap.

Task Coach - Task Coach is an open source personal task manager providing features to deal with complex tasks.

TaskFreak - Simple web-based task manager written in PHP.

Total Text Container - An open source information manager; stores notes, passwords, images, calendar events etc.

Achievo - Easy to use and customize open source web-based project management application for business environments.

AgileTrack - Java based application for monitoring and tracking activities in a software development environment.

ASTS - A set of web based management tools for recording project activities and tasks.

Austin - A command line utility for manipulating project timelines in XML.

dotproject - Open source Project Management application developed and supported by a group of volunteers.

Double Choco Latte - A basic project management application used to track the history of work orders, projects, accounts etc.

eHour - User friendly web-based tool for keeping track of time based activities; ideal for consulting companies.

FreeMind - A mind mapping application useful for brainstorming sessions.

FUTURe - A time management application for individuals and groups.

Ganttproject - Written in Java, and using XML file format; enables project planning through a Gantt chart.

JIRA - JIRA is a project management & task achievement application for making team processes easy.

jxProject.com - Cross platform project management tool with sharing options.

IPM - A simple project management application built in PHP4 and requiring Apache 1.3x and MySQL.

Memoranda - For users handling multiple projects on a daily basis Memoranda is an ideal tool.

NetOffice - An online project management application for managing tasks, projects, team tracking and collaboration between teams.

Open Workbench - Excellent Windows-based application providing project scheduling functionality for enterprise users.

Planner - Project management tool for the Gnome desktop that is useful for project scheduling, planning and tracking.

phpCollab - An open-source internet-collaboration tool for project teams allowing them to share information amongst each other.

project-open - A web-based project management system for small consulting and service companies. Covers sales, project planning, collaboration and CRM.

Projectory - Projectory is an open source web based project management tool for tracking software projects through development phases.

Projman - A project management tool for reading project descriptions and their scheduled tasks.

Rapla - Highly configurable event and resource management application primarily targeted towards universities.

Taskjuggler - A powerful tool with redefined approach towards project planning activities, taking it far beyond the commonly available tools for Gantt charts.

Trac - Wiki and issue management system for software development projects.

TrackIt - An open source web based project tracking tool to maximize flexibility and customization.

TUTOS - Organization management tool for satisfying the requirements of small groups, teams and departments.

User Story .NET - A tool for extreme programming projects in user story tracking.

WebCollab - An easy to use collaborative project management system enabling users to work together.

WebPBC - Web-based project management tool for small businesses to do budget allocation of projects.

XPlanner - Another web-based project management tool for eXtreme programming (XP) software development practices.

BIRT Project - An Eclipse-based reporting system.

DataVision - A reporting tool that works with any database and generates customized reports.

Jasper Reports - A leading open source reporting engine delivering rich screen content and printer into various file formats: PDF, HTML and XLS etc.

JERT - JavaEye Reporting Tool is a web-based database reporting tool with sharing features. It enables users to create flexible reports without any programming knowledge.

iReport - iReport is an easy to use visual report builder designed and written purely in Java.

openi.org - Pronounced as “open eye”, this is a web-based open source OLAP reporting tool enabling organizations of different sizes to manage and organize their data.

OpenSMART - Similar to Tivoli, a monitoring and data reporting tool for servers.

Pentaho - Open source business intelligence tool enabling organizations to operate more effectively by providing reporting, analysis, workflow capabilities.

Rapid - I - Offers all types of data mining services (from analysis to customization) helping customers to improve their profitability and efficiency.

SpagoBI - Focused business intelligence solution for the enterprise providing complete set of analytics (e.g. reporting, data mining, dashboards etc.)

xTuple - Open source SQL report writer compatible with Windows, Linux and Mac.

Aggie - Aggie is a desktop based open-source news aggregator that downloads the latest news in a webpage.

AmphetaDesk - A cross platform, open source news aggregator that downloads news items on the user’s desktop.

BlogBridge - A powerful and flexible desktop based open source feed reader for Windows, Linux and Mac.

BottomFeeder - RSS news aggregator client written in Smalltalk and compatible with Linux, Windows, Mac and Solaris.

Gregarious - A web-based RSS/RDF/Atom feed reader designed for users to run on their own web server.

JRssReader - A fast, Java based RSS & RDF reader; offers compatibility with multiple platforms.

NewsFeed - Flexible RSS/RDF/Atom aggregator for different operating systems like Linux, MacOS and FreeBSD.

NRss - an “open source Microsoft .NET Framework / Mono class library for reading a RSS feed into a tree of objects mapped to elements in the RSS feed.”

RSSOwl - Java-based open source news reader.

Syndirella - Syndirella is an open source desktop information aggregator providing a user friendly environment for reading information from multiple sources or feeds.

ThinFeeder - Very powerful and tiny open source aggregator for RSS/Atom developed in Java language.

7-Zip - High-compression open source archive utility for Windows with support for 7z, ZIP, GZIP, TAR files etc.

Amanda - Network backup solution.

Bacula - Set of open source computer programs for managing network backup system for Linux/Unix, Mac and Windows clients.

BiGZip - Free compression utility based in Java.

Burn - An open-source CD and DVD burning application allowing users to create audio, data and video disks in different file formats.

CamStudio - Open screen casting application allowing users to capture audio and video and store it later for playback.

CDRDAO - Open-source tool with advanced features for recording audio or data CDs.

coLinux - Cooperative Linux allows users to run Linux parallel to Windows on any machine.

Cream - An open source text editor with interactive user interface, pull-down menus etc.

G4U - Open source cross-platform hard disk image cloning application.

GrenEye - A file slicing and compression utility.

GNU zip - A compression utility.

GParted - Fantastic open source partition manager with direct boot facility option from CD or USB.

Handbrake - A multiplatform DVD to MPEG-4 converter/ripper with ability to process unencrypted and whole DVD files.

InfraRecorder - A freeware CD/DVD burning application for Windows.

Info-ZIP - Provides high quality, portable versions of zip files compatible with DOS.

Inno Setup - Another open source installer for Windows applications with integrated Pascal scripting engine.

InstallJammer - Useful for creating self-contained cross platform installation packages.

jEdit - A cross platform open source text editor written in Java with consolidated features from major editors.

Emacs - An extensible, customizable, self-documenting open source text editor.

K3b - An open source application for creating/burning CDs and DVDs; packed with features like DVD encoding, copying and audio CD creation.

Launch4j - An open source wrapper for jar files that supports Mac, Linux and Solaris.

Nagios - An open source network monitoring service for hosts, networks and services which use plug-ins.

NeDi - Open source network discovery, inventory & management framework utilizing scheduled discovery for network examination.

Notepad++ - An open source alternative to Microsoft Notepad with features well suited