An interesting and comprehensive
documentary about the Amen break (QuickTime video), giving examples of its history from The Winstons' B-side
Amen Brother to its influence on hip-hop and jungle, its appropriation and fetishisation by pretentious people with PowerBooks, and its subsequent ubiquitification into the wallpaper of consumer culture, and the (increasingly paradoxical) issues of copyright.
(One of the claims made is that The Winstons do not defend their copyright of the Amen break, though that hasn't stopped sample-CD companies from releasing their own versions of it and claiming copyrights on them.)
(There's also one on the cultural history of the Roland TB-303, though I haven't seen that yet.)