The Community Builder (CB) suite extends the Joomla! user management system, and allows you to use Joomla! to build a customizable social networking Web site. Its key features are extra fields in a profile, enhanced registration workflows, user lists, connection paths between users (friends), administrator-defined tabs and user profiles, image upload, front-end workflow management, and integration with other components, like PMS, Newsletter, Forum, and Galleries. Many plugins are available for adding more features. CB is compatible with all versions of Joomla! 1.5 native, Joomla! 1.0.x native, and Mambo 4.5.2-4.6.5. CB allows multi-criteria user searches, full field controls of core fields, AJAX email and username checkers, image and integer fields, custom validations, and many more features.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.