Auto Zip->City

Hi.

Is there an addon or has anyone made an addon that automatically fills out the shipping address city based on the zip code? We have access to a database for Norway with all the zip codes and corresponding cities. So it should not be too complicated to add this to a database and get cs-cart og fill out the correct city based on the zip?

Maybe not an issue in Norway, but in US, a single zip code can belong to multiple cities since the post offices (zip code) often serve more than one community.