zip code

I'm building a directory and have created a (CCK) content type that collects location info using Location and Gmap. I have a lot of entries and would like to auto-populate the city and state fields in the location input by providing just the zip code . Is this possible or would there be a module out there that might do this?

I have created the zip code table in the data base using the zip_codes.us.mysql file that's included with the location module.

Am making sites for Philippine audience and need above.

I could've sworn I read somewhere (might be the php list) that someone was willing to share theirs.

If someone would be so kind as to share this with me, I will use it as per share and share alike policy.

Or if someone knows where I can just get one, please show me the light.

TIA
Gary