This pretty much just applies to those of you who have your own custom carts....
I searched around the web and this site but haven't found a good reference for shopping cart fields. We are currently US only and adding international sales.
Telephone fields that are US 123-456-7890 won't work. Also there are provinces and often letters in the postal code field etc etc.
We have always been pretty strict about data conformity - like no letters in the zip field - in order to minimize errors. So, we could make bigger fields which would be flexible, but the quality of user entered data would surely suffer.
Thought about having some kind of java app that would ask your country first, then serve up a custom form with appropriate fields like province etc.