Google is your friend: Be nice and visit him often. He can answer questions a lot more quickly than posting them here...
A very quick search using your subject as the search term gave over 200,000 hits.
The top result was an example: http://mamoonblog.wordpress.com/2012/01/17/get-address-by-postcodegoogle-geocoding-api/
In future, please try to do at least basic research yourself, and not waste your time or ours.