These are some of the links I use to obtain some of my information.
Most of these links are directed twards the farrier. However, all of these have useful informaition for the horse owner.

Horseshoes. com This site contains a wealth of information. It provides a wealth of articles, a bulletin board, and a farrier market place. Not to mention many other admiral qualities.
American Farriers Association This is the site for the AFA, contains certification info., and dates, related links, and a farrier finder.
Anvil Online Home to Anvil magazine. Has farrier and blacksmith articles. Great recourse site.
American Farriers Journal Another great resource page. Home of the official journal of the AFA.

Hoofprints.com This is a great site if you are looking for farrier products.