If you recently purchased an iPhone 4 and tried to connect it to your MacBook, Mac Mini, or iMac running Mac OS X 10.4, you’re not alone in your frustration. Connecting an iPhone 4 to a Mac with Tiger aka OS X 10.4 results in an error that tells you your operating system won’t work with the phone. If you’re running a Mac without an Intel processor, you probably need to consider an upgrade to new hardware because Apple is making it increasingly hard to upgrade PowerPC Macs. If you have an Intel Mac, you have one of two options, one of which is cheaper, but also a violation of the terms of service.
Option One: Buy the Mac Box Set, which includes iWork 09, iLife 09, and the upgrade to Snow Leopard which will make your Mac compatible with your iPhone. Apple sells this upgrade bundle for $169, but you can typically find it on Amazon (linked above) for under $100.
Option Two: Buy the Snow Leopard upgrade for computers running Leopard. This method will work and it only costs $29. There are downsides. For one thing this violates Apple’s terms of service, because the $29 upgrade is only meant for upgrading from Mac OS X 10.5 Leopard. The other downside is you will need to do a clean install, which means any other apps you installed will need to be reinstalled on Snow Leopard.
Either way, once you finish, you will have a Mac that works with your iPhone.