I have an iMac G4, iBook G4 and PB G4 all running OS-X 10.3.9. I need to upgrade to OS-X 10.4 in order to install certain external hardware (e.g. Airport) and other 3rd party software. I am reluctant to go to OS-X 10.5 (Leopard) not that it would be any easier to find because I have some older OS 9.x applications I still use. I have checked Amazon, eBay and others but the prices for the retail version (allowing installation on different Macs) is over $200. Does anyone know of a good source for previous versions of Mac OS system software specifically OS-X 10.4?