I'm not all that familiar with the Little Big Horn battle, but it was not Custer's charge. A History Channel program I saw a few years ago indicated, through a forensic study of the battlefield, that it wasn't actually a stand, either. The soldiers were forced back and separated, then surrounded and killed.
Wikipedia has a pretty good account here. http://en.wikipedia.org/wiki/Battle_...Little_Bighorn
As for the Light Brigade, I know almost nothing except that the whole battle was a fiasco, something which should never have occurred.