A good source of information is magazines, and there are a lot of them directed to horse owners:
Horse Illustrated Magazine: A complete source to help you better care for and enjoy your horse. Also, each month includes a gallery of full-page photos of beautiful horses. Published monthly.
Horse & Rider Magazine: All about western riding, training and horse care. Published monthly.
Practical Horseman Magazine: How-to and training for English riders of all disciplines. Published monthly.
Young Rider Magazine: Packed with features, facts, photos and fun stuff about horses and ponies. Published bi-monthly.
Dressage Today Magazine: That’s, right, all about dressage. Learn this Olympic equestrian discipline from the world’s top trainers and riders. Published monthly.
Hobby Farms Magazine: Hobby Farms is edited for all rural enthusiasts. It speaks to small farmers working for their livelihood, part-time pocket farmers trying to make a profit and hobby farmers who just enjoy the lifestyle outside of their day jobs. Each issue features new products, tips, tools of the trade, and more! Published bi-monthly.