It is easy to asume that this is a nobrainer feature that should have being done long ago, and I suspect that this have being excluded in iPhone OS due to copyrights and licensing of the IP involved.
If that's the case, then that's really sad. All of these stupid patents, licensing, etc. is going to crush American innovation. It's OBVIOUS that devices will sync over WiFi (and whatever else comes down the pipe). If there are people holding patents that prevent others from including such OBVIOUS features, then our patent system is even more wretched than I imagined.