Take a peek at this extensive archive of classic animation: The Hollywood Animation Archive Project.
My favorite section on the site is an animation course that steps through a book by a legendary animator, Preston Blair. His book provides simple, fundamental instructions for animation. The “course” is lead by John Kricfalusi, aka John K., the creator and animator of Ren and Stimpy (among other shows). The lessons seem simplistic, but they are actually very informative and helpful.
One last thing — in case you missed my post below, check out the new University State section and videos on PiVisuals.com.