Hi Scott -
Well, there's Digital Character Animation, by Steve Roberts, which gives you a good grounding in the traditional cel animation, how it's done, and good motion references.
There's Animation, From Pencils to Pixels, by Tony White, which gives a great history of animation, and then flows into techniques.
There's How to Make Animated Films, also by Tony White, which gives a broad overview of the different processes used in Animation.
And there's the king of the hill, The Illusion of Life: Disney Animation, which gives a very detailed overview of character animation Disney style. It covers squashes, stretches, walk cycles, in-betweening, weight, character appeal, timing - it's an exhausting tour-de-force of animation, and it's expensive.
Most of these books can be found on *bay, so you can save some money on them, or from Focal Press, if you want to support a good publisher. Look them over to decide which one fits your needs. Of course there's also the Muybridge motion studies, the first master study done on human and animal locomotion using stop motion photography:
http://www.muybridge.org/Animal-Locamotion-finished-1/Animal-Locamotion-Vol...
Joe Bourke
Owner/Creative Director
Bourke Media
http://www.bourkemedia.com