A friend of mine has a PowerPC iMac G5. We are not sure which exact model it is, but I had a look on MacTracker and the G5 iMac models that look like it that originally came with 10.3 are supported by 10.5. Borrowed a genuine copy of 10.5, and whenever we try and install it from both the desktop and by C at startup, we get some sort of kernel error... I'm sorry I cannot provide any more details. I was wondering if anyone had any suggestions on what could be done next.