Forward geocoding from the iPhone
iOS 5 now allows for forward Geocoding:
http://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/LocationAwarenessPG/UsingGeocoders/UsingGeocoders.html#//apple_ref/doc/uid/TP40009497-CH4-SW5
I hope this helps!
I've created a forward geocoding API for Google's geocoding server. Check out my blogpost: http://blog.sallarp.com/ipad-iphone-forward-geocoding-api-google/