iTunes 9.1 is now available. New features include support for the iPad, and ebooks purchased from the iBookstore—which is expected to launch with the iPad this Saturday. Also new in iTunes 9.1 is the ability to rearrange, rename, and remove Genius mixes.
Despite this, jailbroken users should be somewhat cautious, and it is advisable to wait for the green light from the iPhone Dev Team.
You can download the update from the iTunes download page.