I’ve seen that it’s possible to get the latitude and longitude (geocoding, like in Google Maps API) from a street address, but is it possible to do the reverse and get the street address when you know what the lat/long already is?
The application would be an iPhone app (and why the app already knows lat/long), so anything from a web service to an iPhone API would work.
Google again
http://nicogoeminne.googlepages.com/documentation.html
http://groups.google.com/group/Google-Maps-API/web/resources-non-google-geocoders