How can I install iTunes 10.6.3 on Mac OS X 10.5.8 PPC?

I am trying to install iTunes 10.6 after a recent upgrade from OS X 10.3.9 to 10.5.8. This version of iTunes appears to be compatible with Leopard and G4 proccessors. The install completes, however iTunes is NOT updated. It remains at version 6. I also tried updating to 8.2 without any luck. I don't want to hear the riot act about how the system is outdated and how I should upgrade. I have my reasons for not buying a new Mac. I know this works because it worked on a friends eMac. Thanks!