Thanks to a post on the Bible Gateway blog, I see that Google Maps recently announced the Google Maps Gallery.
Maps Gallery works like an interactive, digital atlas where anyone can search for and find rich, compelling maps. Maps included in the Gallery can be viewed in Google Earth and are discoverable through major search engines, making it seamless for citizens and stakeholders to access diverse mapping data, such as locations of municipal construction projects, historic city plans, population statistics, deforestation changes and up-to-date emergency evacuation routes. Organizations using Maps Gallery can communicate critical information, build awareness and inform the public at-large.Basically what is happening is that organizations can share maps as overlays on Google Maps. There is a transparency slider that allows you to control the visibility of the overlay and the underlying Google Map. With the Google Map, you have the choice of displaying it as a map--with or without terrain shading--or satellite view.
Among the maps are a number of Lands of the Bible maps from National Geographic from 1938, 1946, 1956, and 1967. The citations of biblical sites does not change much in those maps, but, as you can imagine, there is a tremendous amount of geopolitical changes that occur over those years.