I have found a new toy, Bing Maps. At first the maps seemed the same as Google Maps, but the new wrinkle is a Bird's Eye feature. This allows you to look at the ground as if you were a bird flying over it. And you can rotate your view so you can see a spot from four different angles.
So for fun I looked at Gettysburg, Shiloh and Chattanooga. From shadows you can pick out ravines and slopes, so you can get a little better idea of the ground than a normal map gives you. Also it is helpful for Missionary Ridge as there are areas you cannot walk on that now you can see. It looks like a lot of the areas were flown in the early spring or fall so there is not a ton of foliage blocking views.
I was a bit surprised that Shiloh was mapped, but not Chickamauga. Chickamauga is near pretty good sized city while Shiloh is a fair distance from a good sized city.
I'm interested to see what other battlefields have been mapped.