Reverse geocoding: the process of converting a latitude/longitude pair into an address. Google now offers this.
"As a live demo of the reverse geocoder, check out
MeetWays, a site that mashes up the Google AJAX Local Search API with the Google Maps API and just a bit of maths. It calculates the mid point between two addresses on the map, uses the reverse geocoder to find out the address for that point, and then does a local search near that address to find places to meet that are halfway between. Since reverse geocoding works in all the places that forward geocoding works, then you should be able to meet up with your friends in more than
70 countries."