Associations: 

United States Equestrian Federation (USEF)      http://www.usef.org/

American Saddlebred Association (ASHA)       http://www.saddlebred.com/

United Professional Horsemen's Association (UPHA)      www.uphaonline.com/

American Saddlebred Horse Association of Michigan (ASHAM)  www.asham.org/

Michigan Horse Show Association (MHSA)      www.michiganhorseshow.com/

Tri-State Horse Show Association      www.tristatehs.com/

Publications:

Saddle Horse Report     www.saddlehorsereport.com/

Saddle and Bridle     www.saddleandbridle.com/

Show Ring Times     www.showringtimes.com/

The Bluegrass Horseman     www.bluegrasshorseman.com/

The National Horseman     www.tnh1865.com/

Riding Apparel:

Hartmeyer Saddlery     www.hartmeyer.com

Commotion Riding Apparel    www.shopcommotion.com

Showstopper Tack     www.showstoppertack.com

DeRegnaucourt Ltd   www.deregnaucourtltd.com

Le Cheval     www.lechevalltd.net

My Trainer's Closet     www.mytrainerscloset.com

The Good Habit     www.thegoodhabitonline.com

Tack:

World Champion Horse Equipment     www.ehorseequipment.com