If you don't want to use HTML5 style client-enabled GeoIP information, you are going to need a GeoIP database like MaxMind's GeoIP Lite database, which is free and works well for 99% of use cases. Any other service with more accurate/detailed information is going to cost you a lot of money. MaxMind is praises by many people and works well for my needs, personally. It can give you Country/Region/City/Latitude-Longitude-Coordinates/Continent information.
