I'm trying to do this on linux atm. I can ping my 770 from my computer now, so the local networking works, but I still can't surf. Check out the following links:

http://maemo.org/maemowiki/HOWTO-BluetoothNetworking
(don't forget this: http://maemo.org/maemowiki/DummyIAP )

If anyone has any idea why my pc isn't forwarding the internet traffic, please let me know.