How do I change my shifter knob?

I own a 2002 Toyota Altezza and would like to purchase the chrome ball-shaped shifter knob that comes on the Lexus is300. How do I remove the old shift knob, inorder to get the new ball-shaped installed? I am not even sure if they can be interchanged...
How do I change my shifter knob?
Look at the shift knob. The lower part should be a ring that you can twist off. (It's probably too tight to unscrew by hand, but if you wrap a thick rubberband around it, it's much easier.) Once you get that ring off, you should see some screws holding the shift knob on. Just unscrew those and you can take off the knob and replace it.