The study of George and the Battle of the Little Bighorn, in addition to being one of the most interesting pastimes for the armchair scholar, is a conclusive demonstration that the study of history tells you as much about the historians and their time as about who and when they're writing about. As common when rating controversial personalities, George has gone through the inevitable cycles of praise and damnation. If one generation of historians say George was a hero, then the next say he was a jerk. We've had about three or four of these cycles, and most biographies written since the 1980's aren't quite as tough on George as those in the middle twentieth century.
The best place to start reading about George is probably one of the many books. (Remember them? Those funny non-electronic devices with white flappy things in the middle?) But for those who believe if it's not electronic, it's not worth reading, you can start out with A Most Merry and Illustrated History of the Battle of the Little Big Horn.