From Matt’s Geography Blog:
The Mother Jones website has an interactive map depicting the presence of U.S. troops around the world for every half-decade since 1950 plus 2007.
Use the slider at the base of the map to see a timed animation of troop strength from 1950 through 2007. Zooming into a region and placing the map cursor on a country lists the number of troops and stationed sites. The site describes the source being Pentagon worldwide troop data.