The geocoding response format has been revamped to offer a number of
improvements, which includes a flatter format, the ability to tag
address components with multiple types, and added support for full
names and abbreviations for countries and states. Here are two
examples of geocoding request/responses, one forward and one reverse:
http://maps.google.com/maps/api/geocode/xml?address=sydney&sensor=false
http://maps.google.com/maps/api/geocode/json?latlng=-33.873038,151.20563&sensor=false
In addition to response format changes, geocoding requests no longer
require Maps API keys. However Maps API Premier customers are
required to
URL-sign their requests to the new service:
http://code.google.com/apis/maps/documentation/premier/guide.html#URLSigning
The old geocoding service has been retroactively named to "Geocoding
V2 Web Service", which will remain maintained and supported in
accordance with our deprecation policy stated in the Maps API Terms of
Service.
Be sure to revisit the documentation for more details:
http://code.google.com/apis/maps/documentation/geocoding/