I don’t notice about any difference everytime I update the Mac OS X. It is not really for the recent Mac OS X 10.5.3 update. It brings the capability to synchronize the address book with Google. With no additional software required, launch Address book and select from the “Address Book” > “Preferences” menu, you will be able to see something like above. Check the option and enter the Google login information, and you will be able to sync it quickly.
Althought I can also sync iCal with Google by using the “subscribe” option, I would like to see iCal sync with Google in the above way.
[via Official Google Mac Blog]
A great way to sync iCal calendars with Google is with BusySync. (See http://www.busymac.com.) Note that I am not affiliated with BusyMac, just a happy customer.