Setup is simple:

Pair the device with your macbook. Its best if you do it from the macbook rather then the phone. Make sure you say that you will use the phone for internet connection. Check SERIAL PORT. Finish that up.

Next.... goto ICS (Internet Connection Sharing)

PC Connection (Bluetooth PAN)

Network connection: ICS

Hit connect.

Then on macbook simply hit the bluetooth icon and "Join Network Treo" Treo is my device name. Yours may be different.

Good luck and enjoy!