A new version of the zip code boundary map has been released today! This one displays actual USPS zip code areas instead of ones based on the Tiger/Line ZCTA's. The results are the most accurate free USPS zip code boundary maps available anywhere on the internet. These new maps are up to date as of November/2006 and will be updated quarterly.
The usual 150 hits per every 120 minute limit applies to this map.
-John Coryat, USNaviguide.com