If you plan to use the panther discs which came with your pb when you bought it, the answer is no.
Panther disc which are bundled with a Mac are related to the bought Mac. The only OS which can be installed on several machines are the retailled one, the Panther package you can separately buy in a store or on the Apple Store.
Same for Tiger, the lattest I would suggest you to install on your PB
Phil

To stief: iMac -> iBook may work..a chance
iBook -> iMac should not work