A question from Yahoo! Answers:

I have a website (using php and apache) and want to know how to find location (country and city) of web users?

You can’t. You can narrow it down by IP address (see www.maxmind.com for information on how to do that), but this method is notoriously unreliable, especially when it comes to dial-up users (AOL users in Germany, for example, often show IP addresses that point to the UK) and users of corporate networks.