I'll start with the two essentials.
Johnston, Ollie. Thomas, Frank. "The Illusion of Life: Disney Animation" Revised edition (October 19, 1995)
The ultimate animation book, filled with Disney related history. There are great tips on how to bring life into your character. You must have this if you like animation. I would say that's all of you!
http://www.amazon.com/exec/obidos/tg/detai...=books&n=507846
Williams, Richard. "The Animator's Survival Kit: A Manual of Methods, Principles, and Formulas for Classical, Computer, Games, Stop Motion, and Internet Animators" January 7, 2002
One of my all time favorite books. I would say it's the best how-to.
http://www.amazon.com/exec/obidos/tg/detai...=books&n=507846
OTHER:
Maltin, Leonard. "Of Mice and Magic: A History of American Animated Cartoons" May, 1990
Maltin covers nearly a century of american animation art in detail.
http://www.amazon.com/exec/obidos/tg/detai...=glance&s=books
Gilbert, Wayne. "Simplified Drawing for Planing Animation" This book is about Simplified Drawing for Planing Animation
http://www.anamie.com/
