Recently the zip code guy blog highlighted a huge database of USA cities, towns, and counties in a wide array of formats. The database includes lists of
- All US Cities
- All US Counties
- All US Zip Codes
- Latitude and Longitude of Cities/Zip Codes
- States and State Abbreviations
For $25 this database is a great investment if you are run geo-local AdWords campaigns using tools like Speed PPC.
This video offers more background on the United States zip code database.