you can try to do a non-native leopard installation, just put the hard drive in a mac that can install leopard, than install it, once it's done, you can put the drive in the ibook. leopard will boot regardless of the hardware, as long as it has enough ram. i did this on my 733Mhz G4, and leopard even reads the procesor speed, as 733Mhz, and it runs anyway. there are also tools that allow you to install it and bypass the specs. leopard is the last PowerPC-Compatible mac os, so there should be a lot of support for it in the future, compared to tiger.