SI usually has good coverage, and always the best photos. I always click on Equestrian every day, figuring the # of hits each sport gets is always monitored.
Anyway, here’s their synopsis of Equestrian, and there’s also a link to their “Explainers” section. It’s interesting to see how sports are explained to the average viewer: http://sportsillustrated.cnn.com/2012/olympics/2012/writers/nick_zaccardi/07/17/london-olympic-equestrian-preview/index.html
Also like SI’s listing of athletes - by name, or by country, or by sport: http://sportsillustrated.cnn.com/olympics/2012/athletes/sport/equestrian.html