LifeHacker suggests a method for keeping your Contacts and Addresses in Sync using the new 10.5.3 Address Book settings only. Apple added this functionality so that iPhones could sync up with Google, but it may be possible to spoof the software by editing plists and running sync against another device or against .mac
The comments don’t providea foolproof algorithm yet, but it seems doable.
Mac OS X Leopard: Enable Google Contact Sync Without an iPhone or iPod Touch
If you don’t have an iPhone or iPod touch and unlocking this useful bit of functionality isn’t worth paying hundreds of dollars for the device, a simple system tweak can turn it on for you.
