SaudiMac

Apple released Mac OS X 10.5.3 update for Leopard, update is recommended for all Leopard users and improves the stability, compatibility and security of the Mac. On my second generation MacBook Pro the update was 198MB. While newer MacBook Pros need to download 420MB.
One of new features in this update is the ability to sync your contacts with Google.
For pre-10.5.3 systems, Security Update 2008-003 was released. For servers Apple also released the Mac OS X Server 10.5.3 update.