Hi Forumboy,
There are no IPs provided with the PMs, so the only way would be to catch his IP while he is logged on.
Log in to the Admin panel and you will see all the IPs of those who are on the forum at the moment. And if you click the IP, a new page opens with a tracking tool, that will give you some kind of network URL and the aproximate location.
I guess you want the IP because you and your members don't like the messages he sends, or something like that. In which case you may want the IP to be able to ban him.
Don't do that, if you can avoid it. Most IPs you get are not to individual computers. You are likely to ban other members, and/or to prevent new members from even finding the forum.
There are other options, and I may as well include them, just in case you want to get rid of the member, or the PMs...
If you don't want him to send PMs, go to:
User Admin >> Management >>
type/paste the name in the field and click Look up user.
You come to the member's profile page.
Scroll down to the botton section, called Special admin-only fields.
There you will find
Can send Private Messages xYes No
Set it to No, and click Submit, and the member will not any longer be able to send PMs.
In Special admin-only fields you also have the option to change this to No:
User is active Yes xNo
Click Submit and the member cannot log on any more.
FoxLeonard