From what I have heard the Dual USB iBook and Powerbook G4 keyboards are not interchangable (while the Powerbook G3 and Clamshell iBook keyboards were). So you can't just take a keyboard for one model and install it on the other. What I would like to know is if the keycaps are interchangable. That is, can you take the caps from the powerbook can snap them onto the ibook keyboard and vice versa? I think they are, but I don't have a Powerbook G4 to test this on.