If you’ve got an internet connection and time to kill, swing over to Wikimapia. Like Google Earth, it allows you to browse through satellite photos and scope out the terrain. Unlike Google Earth, it allows visitors to mark and describe features of interest. History buffs have gotten in on the act, so you can do some nifty virtual battlefield touring.
Since Wikimapia is a collaborative project, the entries reflect popular interest. The most thoroughly-documented sites are the famous Civil War battles. Gettysburg is marked up like crazy; even the Longstreet Monument has a notation. Antietam and Shiloh also have some great detail. That’s not the case for the Revolutionary War sites. Check out Cowpens, King’s Mountain, Lexington Green, and Yorktown. I tried searching for some War of 1812 sites, but most of them didn’t turn up any results.