Update: iPhone SDk 3.0 now addresses the question here, however the NDA prevents any in depth discussion. Log in to the iPhone Dev Center if you need more info.
Ok
Since iOS5 we have the following options as stated in the development doc: * "A geocoder object uses a network service to convert between latitude and longitude values and a user-friendly placemark, which is a collection of data such as the street, city, state, and country information. Reverse geocoding is the process of converting a latitude and longitude into a placemark. Forward geocoding is the process of converting place name information into a latitude and longitude value. Reverse geocoding is supported in all versions of iOS but forward geocoding is supported only in iOS 5.0 and later."*
You can now use a CLGeocoder object.