Horse

Medieval Cavalry Charge
Essay on La Régle du Temple manual to the mediaeval and crusader horse charge.
http://www.deremilitari.org/resources/articles/bennett1.htm

Society of the Military Horse
Wide-ranging discussion forum on horse cavalry across nations and historical periods.
http://www.militaryhorse.org/

Stirrup Thesis in China
Silkroad Foundation article on the effect of horse cavalry on Chinese history.
http://www.silk-road.com/artl/stirrup.shtml

Stirrup Thesis in Europe
Jesuit University article on the effect of horse cavalry on European history and the emergence of feudalism.
http://www.fordham.edu/halsall/med/sloan.html

US 1907 Saber Exercises
Scans of the original American army cavalry saber drill, for mounted and dragoon combat, written by George Patton.
http://www.anesi.com/prsefs.htm

US Cavalry Association
A non-profit organization for the study and perpetuation of the traditions of the American cavalry, modern and historic. Hosts the annual National Cavalry Challenge.
http://www.uscavalry.org/

Wikipedia: Cavalry
Open encyclopaedia article on the history and evolution of mounted warfare.
http://en.wikipedia.org/wiki/Cavalry