I’ve put together a similar service over at http://www.fosterburgess.com/v2/random.php. While it’s not downloadable (yet? probably a good idea), it does generate more accurate data than the one you listed with respect to state/ZIP codes. Benjamin’s shows a postal code of “J3F 8N9″ for state “Maryland”. I think his is more truly ‘random’ than mine, which takes random ZIP codes from a ZIP code database, and then uses the corresponding city and state with that ZIP code. I don’t deal with Canada or other non-US areas, though, so if you need that, it may not be a good fit. Any suggestions on improvements are welcomed as well.