Today Steve Jobs made a grand reappearance on the Apple stage to introduce iTunes 9 at Apple's Rock 'n Roll event in San Francisco. So what's new?

1) iTunes LP is a new incentive for full-album purchases: you get images, interviews, liner notes and all the original album material that don't usually come with digital downloads.

2) Home Sharing allows you to share all the albums, shows, movies and music in your iTunes collection with up to five computers in your household.

3) Even better: you can share apps between your handheld devices (iPhones and iPod touches) so you never have to buy an app twice.

4) Improved syncing lets you sync by artist or genre, as well as playlist.

5) New clean interface. That's the kind of smart design that is Apple's speciality, and as iTunes gets more bloated, also Apple's imperative.

6) App organization. Now you can organize and lay out iPhone and iPod apps right in iTunes, so you're not dragging your index finger to a wobbly demise.

7) More Genius. Specifically, Genius can now make you mixes instead of just finding similar artists. Steve says it's "just like a radio station." I say it's just like the thoughtful boyfriend or girlfriend you always wanted.

8) Sharing with the Social Web. A new arrow next to the "buy" button in iTunes allows you to send the music as a gift, make a wish list, or tweet that list to Facebook and Twitter.

9) Available today. Lucky you!

Images courtesy of Gizmodo.