this should do the trick (I haven't tested it yet but it looks like it can do just what you're looking for)
http://code.google.com/p/android-pho...downloads/list
EDIT,
Just tried it out and it looks like it doesn't actually use gps coordinates but instead cell tower coordinates.
Showed my location about 2 miles off.
edit 2:
Tried again with gps on (had google maps running) and the location was spot on.
Even gave me the street address.
so i guess its great if you have the gps running in the background, but otherwise don't expect an exact location.