Stallman talks about the origins of copyright law, and describes how our idea of content ownership has changed over the past few hundred years. He also picks apart current copyright laws (including the bullshit DMCA), and sets out an alternative system in the context of modern production and distribution systems (you know, the internet?). If you like the lecture, also be sure to check out Lawrence Lessig’s Free Culture, a book that’ll change the way you look at “ownership” (and that you can download for free in PDF format).
The Stallman file is huge, and the video is completely unnecessary (I’d actually recommend not watching the video–Stallman isn’t the most, er, elegant speaker), but if you’re at all interested in copyright, it’s worth the wait. You’ll also need software that plays .ogg files, but that’s easy–Miro (formerly known as “Democracy”) will open ’em no prob.