Here's a few sites that may interest you on your quest for horse knowledge:

Horse Associations and Clubs

• American Farriers Association
• Ontario Farriers Association
• Brotherhood of Working Farriers Association
• Western Canadian Farriers Association
• Farriers Registration Council of Great Britain
• Farriery Training Agency of Great Britain

Misc.

• Horseshoes.com is a website known for their extensive libraries of horse knowledge, but mainly for the excellent forums that are populated with full-time farriers, vets, and horse owners from all walks of life.  If you've got a question or a peculiar problem that needs solving, there is bound to be a competent horse person that has the knowledge you need found here.
• Free Horse Coloring Pages - an extensive list of websites that have free coloring pages on horses.  Great for your kids
• Equine Lameness Overview Page - A page related to some of the varying lameness conditions that can be found in a horse.
• List of Horse Breeds - a huge list of horse and pony breeds found at wikipedia.
• List of Horse Coat Colors - this site has a great overview of the different colors of horses, with some extensive discussion on genetics.