Here is the most recent audio interview with Richard Stallman. In it he introduces the basics of the Free Software philosophy, but in a further discussion also explains some other interesting things such as the fact that Free Software is actually more in accord with the free market capitalism than proprietary software, the reduction of freedom that is going on in the world (specifically mentioned US and UK) and also Stallmans motivations for advocating freedom.

It is an excellent easy to listen interview. Ogg is available here.

This is a full transcript of the Richard Stallman's speech that I visited in March last year. It should be a good read.