I’m looking for something similar to this:
http://www.usnaviguide.com/zipunion.htm
were a person can put in a zip code and it maps it on Google Maps, then you can click around that area on Google Maps and it highlights it on the map and adds that zip code to the list.
this site has more information on how it works and many comments with suggestions:
and this might also be useful
http://code.google.com/apis/maps/documentation/javascript/v2/examples/
