UpNext has released an update to its interactive 3D city map application for the iPhone and iPod touch, adding support for three new cities and integration into the Foursquare location sharing service. In addition to New York City, the update now adds 3D maps for Boston, Washington, DC and Austin, Texas. Integration with Foursquare now allows users to see checkins from Foursquare directly on the 3D maps, and the updated version also provides menu…
