Replying to Iphone/Macbook help! (technical NSers)

With the Iphone 3.0 update that came out last month came the ability to Tether your iphone to a macbook and use the 3G capabilities anywhere where your carrier would support your phones 3G, on your macbook. You can do this over USB connection or Bluetooth, this is where my predicament comes into play, i can tether using the USB but i cant tether over bluetooth, am i missing something? please help !
+k

SPARKNOTES: Does anyone know how to tether their macbook to their iphone over bluetooth?