The Thief Archive, the YouTube project to try and keep The Thief and the Cobbler alive, has uploaded a documentary done by the wife of Richard Williams, Imogen Sutton, on pioneering animator Art Babbit (read an interview here). She took full advantage of her access to the production of Thief, and uses it as an introduction into the life and work of one of Williams' lead animators. It's a great overview of animation history as seen through the lens of one guy's life. I especially like the insight into Goofy, which is, both technically and for sheer entertainment value, Disney's best character.
And just for a bonus, here's a behind the scenes for Roger Rabbit that aired in CBS back in the 80's.