Are there a full list of zip codes?

[blackhorse]

I am working on an e-commerce site, and we will adjust the shipping cost by the state. So far it is fine.

Where I can get a full list of the zip code? Just in case if the client want to go further later on adjust the shipping cost by the zip code?

How often the zip code changes (such as new zip code added)?

Personally, I think for a small size business adjust the shipping cost by state is good enough. Adjust the shipping cost by zip code will bring too much unnecessary works for the merchant and the shipping cost difference (by state or by zip code) will be very small.

Does zen cart or oscommerce have this feature or 3rd party plug in for adjust the shipping cost by zip code?

Thanks!

[NogDog]

For US zip codes, the USPS has zip code databases that are updated periodically. I do not know off-hand what the cost is (though I'm pretty sure it's not free), but I'm sure you can dig it up at usps.gov.

If your client ships via any of the major carriers, most/all of them now have web services you can access for real-time shipping cost estimates.