Ronaldo82k, just because you have their IP address (which as others have pointed out, isn't really too difficult to do), that does
not mean you can find their location.
Nearly everyone you meet on the Internet is using an ISP (Internet Service Provider) to connect to the Internet. The ISP registers a block of IP addresses for their users, so if you do a reverse DNS lookup, the best you'll get is the address of the ISP's administrative offices. Try that on one of the 50 million AOL users and you'll get an address in Virginia (where AOL is based). The user may be in Calfornia or even further away. But at least you'll know what planet they're on.