Catalog.php page:
Either a State edit check, or use a drop down list.

Address line, need 2

Zip code edit check for valid zip codes.

Country line needed.

Identify required fields: (*)

when any field has invalid entry, need some kind of idiot proof way of informing the user of what is wrong and then returning them to the bad entry line. such as a dialog box that states the error with an "OK" button which then returns them to the bad entry line.

Just some of my .02¢