Seems like everywhere I look these days people are posting tutorials and training videos for classical hand-drawn animation .
The latest tutorial website to go up is Tony White's Desktop Academy of Traditional Animation.
He has the first free tutorial up on the subject of Keys, Extremes, and Inbetweening:
Desktop Academy Tutorial 01 - Inbetweening
For those of you who don't know about him, Tony is the author of the excellent books
"The Animator's Workbook",
"Animation from Pencils to Pixels ~ Classical Techniques for Digital Animators"
and the new book
"How to Make Animated Films" (to be released in June, 2009)