It appears that iTunes 10.3 is available for download in certain areas. Even though I can’t see to be able to hit the update, some people are currently downloading it.
iTunes 10.3 will allow you to automatically download new music, app, and book purchases to all your devices. The automatic downloads and downloading of purchase history are available now but they require at least iOS 4.3.1 on iPhone 3GS, iPhone 4 (GSM model), iPod touch (3rd and 4th generation), iPad, or iPad 2, or a Mac or PC with iTunes 10.3…
I’m not sure yet if it’s safe or not for jailbreakers. You might want to hold off on that, just to be on the safe side.
Update: It’s safe for jailbreakers, so go ahead.