I’m being a little slow to write about it, but John Chaffee gave the XCoders group a nice presentation of synchronization services with the beta launch of BusyMac. It’s a Mac to Mac sharing mechanism to pushes and pulls calendar updates between computers – automatically resynchronizing things after a disconnect and very reasonably dealing with conflicts. For an all-Mac family that it trying to maintain calendars, it’s a solution that you don’t get without having a server somewhere doing that synchronization for you.
It’s not cross platform – so there’s no real sync setup to Google – although it’s completely possible to have one computer syncing from Google and the others reading from it. As John pointed out while we were poking at it, you just don’t want to “close the loop” and end up getting cyclical updates spinning through multiple systems and causing a loop of updates that never really ends.
Although the demo was in Tiger, John was talking about it being a “Leopard only” product. They may well have recanted there though, as the Downloadable demo is available for both Tiger and Leopard.