In the PokerTracker forums there's a post about how to set up postgres. Convert all your DBs to postgres on the one machine. It'll have a service running. By default on PT when you use postgres it sets the server to localhost. On your laptop you'll need to have PT connect to whatever the IP is of your desktop on your local network (a 192.168.0.0/16 address).
Once you go through the guide for setting up postgrest proper you'll see that this is not very difficult to do as all you need to do is change one value in PT for whatever remote computers you're using. If you have a firewall you'll need to allow traffic into that port from your remote computers. For all intents and purposes you can just grant blanket trusted access to 192.168.0.0/16.
If you're still confused send me an IM on AIM... username FireDAW.