My friend Vince Waldron (whose website on classic situation comedies you should also visit) suggests I tell you that the Preston Blair books on animation are still in print.
How to Animate Film Cartoons and Cartoon Animation are the two main ones. They feature wonderful artwork which you'll recognize, not only because some of it appeared in classic cartoons, but because beginning cartoonists are always copying from these books. I can't tell you how many times I've seen the drawing of the cute pig in ads, murals, amateur comic strips, etc. The books also explain the principles of animation in clear, easy-to-understand language.
Cartoon Animation (The Collector's Series) is a fancier compilation of material from both books. I'm not sure if it contains anything that isn't in the other two, but it may. The Blair books have been packaged and repackaged so many times that I've lost track of what's in what edition, and my copies of the first two are very old, anyway.
Among animators and cartoonists of a certain generation, these volumes are sacred. Very few folks who got into the business — or just messed around with the art form — weren't inspired by what Mr. Blair committed to paper. Even in the era of computer animation, there's still much to be learned from him.