Oklahoma State University
Oklahoma State University: Breeds of Livestock Horses
For a very good primer on horses, visit this site. It contains an alphabetized listing of different types of horses, and the pages include the history of various breeds and their physical features.
American Museum of Natural History
American Museum of Natural History: O Logy: Beautiful Breeds: Quarter Horse
Detailed illustrations and description of the quarter horse, known for its speed over short distances. Choose quarter horse from the list on the right.