If you've never heard of Glenn Vilppu, and you're into animation, then its about time you get introduced. Glenn is an amazing figure drawing instructor that emphasizes body language, attitude and gesture over realism. This makes him an ideal teacher for animators who are all about the action. I had the pleasure of taking one of his courses while I attended SCAD. My drawing skills increased triple-fold in that short time. He has a book out that explains his theories, called the Vilppu Drawing Manual. I recently came across an archive of some of his lessons on AWN. They're definitely worth a read if you can find the time.
Vilppu Drawing Lessons.