I've put together 14 high-quality original podsafe instrumental tunes from my Penmachine Podcast into a CD album you can buy. It also includes a bonus data DVD with a bunch of cool stuff that isn't on this website. Find out more...
This page (another one from Darren) links to a QuickTime video providing a fascinating analysis of how a single drum break from a 1969 single B-side (not by James Brown, but "Amen Brother" by the Winstons) found its way into a huge variety of different music via sampling, dub plates, and crazy digital processing. An "entire subculture" based on six seconds of drum break from 1969, in fact, as the narrator says.
The copyright issues get really weird near the end, but there's good commentary in it, and makes a good argument for the possibilities inherent in freely sharing and borrowing sounds. It argues the same reasons why my music is pretty much all free for people to sample, remix, webcast, and so on.