MGeocoder: A Geocoding Google Maps API Extention:

location based services

"The Google Maps API lacks a Geocoder. This extension integrates free geocoders (for non-commercial use) directly into Google Maps.
Click the 'Geocode' button in the map above to search for US addresses, or International cities.
How: Adding a geocoder to your Google Map is as simple as the following Javascript.
For version 1.. "