Simple google search produces this in the first link.
Straight from VZW.
How to Use It
To Activate:
Press *72.
Enter the phone number where you want calls to be forwarded. (e.g. *72-908-123-4567).
Press SEND and wait for confirmation. You should hear a confirmation tone or a message.
Press END.
To Deactivate:
Press *73.
Press SEND and wait for confirmation. You should hear a confirmation tone or a message.
Press END.
Just a heads up when you call forward you still use your minutes. So if you call forward to a land line and talk an hour thats an hour against your plan.