Getting Geographic Location(country) of internet user ASP.NET C#

Here is a FREE web service that will give you Country information from IP address.
http://www.webservicex.net/WS/WSDetails.aspx?WSID=64&CATID=12

But if you want to pay and get more featured service, then you may check here
http://www.ip2country.net/ip2country/lookup.html
This website does not sell Web Service, rather they sell lookup DataBase. You will need to purchase a database from them and then use your ASP.NET look up query to get county information.