>>Hi everybody,
>>
>>Just want to ask you about your experience with various address standardization products and address verification products.
>>
>>Thanks in advance.
>
>Strange - no replies.

Actually there's one - USPS has a webservice. When I get response mail, or just any junk mail, with the additional four digits to the ZIP and a reformatted street number, I know where they got it, it's always formatted the same way.

Don't know how much do they charge, if anything, for pulling data from that web service. It seems to try to match the address with its databases, and then returns a reformatted address with extended ZIP if successful. Don't know how to get it, though, but I guess it's up to you and Google to find a way...