get ip address of web user

are there any free web services out there that will detect the IP Address of the开发者_如何学运维 user accessing your site, and then give you information like zip code, and local?

I am using C# on VS2008.

Request.ServerVariables["REMOTE_ADDR"] to get the IP?

I believe you can use http://www.ip2location.com/

If you want to store that database of IPs locally, you could use Maxmind, it has a C# API and a free IP->location database (and more accurate paid one).

Check this old SO thread for some web services.