While poking around the web a few days ago, looking for a helpful map of the American revolution, I happend upon this fantastic website created by the folks who teach history at the U.S. Military Academy.
The site has all kinds of battle maps for the major wars in which the U.S. has participated.
Beyond that, there is stuff like this animated presentation of the Southern Campaign of the Revolutionary War. Just click anywhere on the slide and follow the path to victory in the South in 1781. This one of the 1776 campaign is fun too.