Outline sales territory on Google Maps using V3 API and a list of Zip Codes

I'm trying to create a t开发者_StackOverflow中文版ool that would take a list of zip codes as the input and would output a google map using the V3 of their API. The area on the map that corresponds to these zip codes needs to be outlined/color.

So far, I can draw shapes and distance circles, but have been unable to add zip coverage. A pointer to a tutorial or some sample code would be greatly appreciated!!!