Saw it work yesterday at the Photoshop seminar. Really looks good, something like a sophisicated version of Picasa and more. The toolset and interface is really catered to photographers. Not that anything that can be done in Lightroom cannot be done in Photoshop, but it's great to see how Adobe is working on something geared to the digital photographer who would spend more time shooting than staring at the computer.
Then again, I'm an 80% Linux user, so I can't use Lightroom unless I boot into Windows (which I'm reluctant). So I really, really hope Adobe can port Photoshop and their whole Creative Suite to Linux!