My mother-in-law is the owner of a old PowerBook G4 12" (CPU Type: PowerBook6,8) and a new iPhone 4. I volunteered to help her with the transition. Until the upgrade she used her PowerBook G4 and iTunes 9.x to sync an iPhone 3G. She cannot upgrade to iTunes 10.x because the newest version of iTunes is not compatible with OS X 10.4.11, and she cannot use her computer to transfer her iPhone 3G data to her iPhone 4 on account of iPhone 4 being unwilling to play with iTunes 10.x. "Just load OS X 10.5," you are likely thinking this moment. I thought the same thing. I even have the Leopard install disc from my not-so-old unibody MacBook (the one that goes by the moniker 'collector's edition'"). But (gasp) it doesn't work! I boot from the OS X 10.5 DVD, the installer attempts to search for 10.4 in the DVD drive and reports that 10.4 cannot be found. >About This Mac clearly displays the current OS as Version 10.4.11. Any suggestions as to why this is happening? Mother-in-law is going bananas.