[Gandalf]

ITGeniusGuru, there's not much point in finding out their IP address. You won't get their exact location -- just the country and maybe the region.

The only thing you could do with their IP address is evil -- directing a denial of service attack at their IP, for example. And in reality, it probably wouldn't be hurting them since they generally "work" from Internet cafes. If one has a problem, they just pick up and move to the next one.

The best thing you can do is simply block them.

Now, if you're determined to find it, I would suggest using netstat. Assuming you're running some flavor of Windows, open a command window (Start > Run > cmd) and type netstat.

With netstat, you can see the active connections of your computer. netstat has options to show either names or addresses, and you can give an interval to refresh, so that it checks and shows connections every, say, 12 seconds.

Like this:

netstat -a -n 12

'netstat /?' will show more options

So if you're computer has an active connection with another computer, e.g. by communication software or file exchange software such as netmeeting, ICQ, Kazaa and other peer-to-peer applications, ... netstat will show that computer's IP address, and the TCP port it is using to communicate with your computer.

Of course, when the communication passes trough a server (eg MSN chat), you'll only see the IP address of that server. You'd have to do a direct connect or file transfer -- something that establishes a connecting with that other computer.