[quote=Bill Campbell]Hey woodyuk!
The answer is yes. Download www.net-peeker.com
Regards,
Bill[/quote]
Wrong. The real answer is maybe.
And you'll never know if you've got the right answer.
As the first reply-er said, you can't know that the other party is connected to you directly. If they are, you'll get the IP address using something like net-peeker.
But the real problem is that you'll have no good way to figure out if the IP you're talking to is the true IP of the caller. It could be their IP. But it might not be. Unless they happen to be calling from a DNS registered IP address that you can whois, you'll never be able to reliably track this information.