>>>>This looks like it might work for you:
>>>>
>>>>http://www.a1vbcode.com/snippet-3557.asp
>>>>
>>>>(You will need a database with the longitudes and latitudes)
>>>
>>>Thanks, I thought there was a formula to calculate from the postal codes directly without having the need to get the latitude and longitude. I'll see more about those options.
>>
>>
>>There's also this http://geocoder.ibegin.com/downloads.php
>>
>>US zip codes with longitudes and latitudes
>
>Cool link thank you!

Oh, I just came across and I thought Michel could use something cheap for a start