Wanted to save this poor Powerbook G4 and change the broken HD.
The iFixit Tuto was great!
Make sure your CD drive still works or pre-install your OS on the drive if you can. My CD-Rom was supposed to work still but when I had finished to replace the HD, the CD drive was ejecting all CDs including the DVD to re-install OS X. You'll need to re-install your os using another Mac through firewire (using the current HD as target drive) or an external firewire DVD-rom in this situation.