Too bad you don't live close by! I've got about 20+ horse books I've collected since a young child. Everything from raising and training baby to horse breeds to riding. I don't know about websites but book stores always seem to have a HUGE selection of horse related books.

One thing I have noticed though, you buy one horse book you've just about bought them all. They use a lot of the same pictures and information Just go check out the book store, you'll find a bunch for under $20.