If the Bluetooth stack in your PC supports LAP, the method and script in following link should work.

http://www.internettablettalk.com/fo...ad.php?t=12666

Actually I have tried this script with my Thinkpad T60 and BlueSoleil,
and suceeded to connect Internet from N810 through BT and T60.
But I can connect Internet from only comand line like as ping or nslookup.
It seems we need to make DUMMY IAP to make Maemo applications to connect Internet. Unfortunetly I don't have enough time and didn't try yet.