I have a presentation layer class that does this very thing for the US and Canada. Goto www.zipinfo.com ans subscribe to their "ZipList5" service for the US - it's very reasonable.

Let me know when you have done so and I will email you the class.

>Does any one already have a zip code / city verifier that is shareware? I want to be able to enter a zip code and have the city and state automatically appear.