Google Earth recently added some maps from the David Rumsey Historical Map Collection to their software, so you can just click them on and off on the globe. Included are a US map from 1833, a 1680 map of Tokyo, Paris from 1716, and a world map from 1790. I spent some time exploring the map of New York from 1836. Here's a screenshot of the southern tip of Manhattan with the present-day buildings turned on:
A larger version is available on Flickr. Google Earth continues to be a fantastic software product. It's almost more of a game than an atlas or educational program...so much fun.
Related: I did a project using Google Earth called Manhattan Elsewhere and made a scrollable, zoomable version of Viele's Map of Manhattan.
