I'm wondering the same thing. My wife and i are both on the road all the time and i want to be able to make a change to my calendar which would change her calendar on the otherside of the world.
I signed up for link2exchange but it deals with more mail sync than anything else. It doesn't really seem to be what i need.
I wish somebody offered just a calendar synch. I've also tried some of the other services but they take a lot to set up and are very unuser friendly. Unless you are some programer.