Open-source software (OSS) is computer software that is available in source code form for which the source code and certain other rights normally reserved for copyright holders are provided under a software license that permits users to study, change, and improve the software. (http://en.wikipedia.org/wiki/Open_source_software#Open_Source_Definition)
List of Some Open Source Software:
1) Ubuntu: It is a computer Opertaing System distributed as free and open source software under a free software licence GPL (General Public Licence).
2) Apache Web Server: It store web documents and displayes them on the Internet.
3) Mozilla Web Browser (Firefox 3.6)
4) OsCommerce: Online shop e-commerce solution. It create website for online shopping.
5) OpenX: It is a ad server software. It is a integrated banner management interface for advertise.
6) Gallery: Web based photo album.
7) Drupal: Drupal is an open source content management platform powering millions of websites and applications. It’s built, used, and supported by an active and diverse community of people around the world. (http://drupal.org/home)
8) Piwik: Web analytics software programme. It gives detailed report of your website visitors.
9) PHP Motion: Easily uploading of videos directly from the user computer (mpg, avi, divx and more).
10) Joomla: Joomla is a free and open source content management system (CMS) for publishing content on the World Wide Web and Intranets.
11) MyPaint: MyPaint is a fast and easy open-source graphics application for digital painters. It provides unlimited canvas.
12) Moodle: Is a free and open-source e-learning software platform, also known as a Course Management System or Learning Management System.
13) Koha: Is a first open source Integrated Library System (ILS).
14) NewGenLib: NewGenLib is an integrated library management system.
15) Greenstone: Greenstone is a suite of open-source software for building and distributing digital library collections.
16) Dspace: DSpace is the software of choice for academic, non-profit, and commercial organizations building open digital repositories. DSpace preserves and enables easy and open access to all types of digital content including text, images, moving images, mpegs and data sets. (http://www.dspace.org/introducing)