More or less. Well, at least Rumsey Historical Maps have been added to the free virtual atlas, which includes the World Globe from 1790, a map of London in 1843, Tokyo in 1680 and Asia in 1710 - to name but a few. The historical maps can be laid over their current location on Earth, so you can easily compare the two. WebTwitcher is sure historians will enjoy playing with this little tool!
You will need to download version 4 of Google Earth (their latest beta) to get the new feature.