advanced stuff
www.gnu.org
Home of the Gnu Project and the Free Software Foundation. The software revolution all started back in 1984 with Richard Stallman. Discover how and why, donate time or money — finish the revolution. One person can make a difference. That person is you.
www.sourceforge.net
The largest repository of Open Source code and applications available on the Internet. Have a peek at cool software both in the making and ready to use. But remember,"Open Source" isn't quite the same as "Free Software". Lots of cool and useful stuff nevertheless.