Hit the down button on the directional pad of your phone. Choose Setup. Choose Find Me. This will make your phone "discoverable" by the bluetooth on your Mac.
On your Mac, go up to the top right of the screen (the menu bar) and select this icon (the Bluetooth icon):
(if the icon isn't there choose System Preferences>Bluetooth>Show BT Status in Menu Bar).
In the BT menu, choose setup bluetooth advice. Follow the steps, and assuming you have a RAZR with functional bluetooth (not always true from what I read on MR and from personal experience!), click on Applications>iSync. Click on Devices>Add a Device. iSync will synch your contacts to and from your address book for you.
If you're running a Verizon RAZR you won't be able to synch to iCal, because Verizon are, at the moment, MScentric.