How Can I figure out who's myspace it is with their IP address?

I have one of those lame "myspace trackers" on my page. It will only give me their town, location, and when they logged on my page. If they aren't on my friend's list, and don't have this specific tracker, they won't tell me who it is but gives me their IP addy. How can I figure out who it is (I think it is an ex... I just really want to know... I guess prove myself something..) with their IP addy? Is there any actual way? No, I'm not a hacker.. just really curious. Thanks a lot.. I know, stupid question.