With all the craze about Keyhole / Google Earth / Google Maps or MSN’s Virtual Earth, it is very easy to forget that cartography isn’t really something new. Navigators, explorers, travellers have been using for over a millenium.
If you want to see ancient maps of France, called the ‘Cassini’ maps, started in the midst of the 18th c., have a look here. Someday, someone should create APIs to them, and help genealogists find ancient villages that have changed names.
Note: see Cassini on Wikipedia.