It does work. From my iMac to me.com to my iPod Touch, the changes on my Address Book are reflected within one minute online and my iPod Touch.

However, you would need to set your MobileMe Sync setting in System Preference to sync “Automatically” for that to happen (see image above).

More details about the changes in the syncing behavior with this update can be found at this Knowledge Base article (via The Apple Blog).