I suppose you could copy the disk image on your G5, and then attempt to burn the image across multiple CDs. However, a) you'll be violating the license agreement (i.e., your iBook's Panther will be unlicensed), and b) it might not work on your iBook. You see, these disks are typically restore disks, which may or may not be compatible only with the machine with which they are included. For instance, I know that the Apple Hardware Test program that comes on these disks is supposed to work only with a specific model.
Sorry to diverge so much. Give it a try and let us know how it goes.
Mike LaRiviere