NPA Lookup

NPA Lookup allows you to retrieve the common city names associated with well-known US and Canadian Area Codes (aka NPA/Numerical Prefix Area). Once you have successfully located the city or area of interest, you can then tap on the city, and NPA Lookup will bring you to the iPhone's built-in Google Maps application so you can integrate this data with your own.

You can purchase NPA Lookup from the App Store.