If you still have the serial number, you should call the manufacturer's support desk and request that they add it to the stolen systems list. Some manufacturers are willing to call you with contact information if they call in.

If you had yahoo messenger or AIM installed you might create a new account and watch for your old profile to logon.
From their you can (sometimes) get the ip address of the pc. Using TRACERT from a dos prompt you can trace the internet path from you to your laptop.
Often the tracert reveals what city the caller is connecting from. This won't help if the caller calls long distance and uses your own internet access number and account to log in.

Check with some computer savy friends who can possibly strike up a chat with the theif and send him a tempting sounding Trojan application that will hang up the modem and dial your home phone number so you can caller id him.

I'll check with a couple of programmer friends and have the app written. Check with me directly. pbcoder at prodigy dot net.

It's also a little scary that he might be reading your email...

Lane