Everything is a Remix

Here is an excellent web video series called Everything is a Remix that explains the history of derivative works and copyright. It is an excellent series. Check it out!
Part 1:
 

Part 2:
 

Part 3:
 
Link to Episode 3 Soundtrack

Part 4:

Link to Episode 4 soundtrack

Along with these videos, an excellent bibliography of samples and references has been provided, if you're interested in the content that was shown. It's very impressive.

Copyright in five minutes, with doodles

Here is an excellent video explaining the far reaches of copyright policy as the world becomes more and more integrated with computing devices. It's well worth your time.