Anyone deveolping something like this???

Heya guys

I'm setting up a new Drupal website. I can't find a module anywhere that can look up a postcode to check if you are in a serviceable area. For example a pizza shop will only deliver a certain distance right? So you pop in your post code and it validates the distance and says yes/no.

Any thoughts? To be honest I wouldn't know were to start with this!

Cheers
Sam Goddard