Geo-location by Zip/Postal Code

I'm looking for a service to get a latitude/longitude dynamically by zip/postal code.

I also need this service to give me an address (city/state/country) by providing an IP Address.

I will be using this service on my website and don't want to download and maintain a database.

I looked at a few services, some too expensive and some free with a max amount of daily/monthly lookups.

What are some good free services and what are some good pai开发者_如何转开发d services (Not too expensive) that allow for a large amount of queries?

I am using asp.net c# with MS SQL Server 2008 or later.

Thanks in advance.

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The US zip codes are free (maybe just not very well maintained): http://www.census.gov/geo/www/tiger/tigermap.html#ZIP

Also see a (whole world) crowd sourcing project: http://www.freethepostcode.org/

The database of the UK zip code location was leaked last year or so. Or maybe it was made public by some government scheme I can't remember. It is definitely available here: http://www.freepostcodes.org.uk/

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For lat/long: Google and Yahoo allow for several thousand queries per day, at least the last time I used them.

For GeoIP lookup, I can't say. In the past, I've used aggregate data from Google AdWords. This may be true of other advertising networks, or some may give you info per user.