Yeah, it's on the iPod Touch. The 2.1 firmware for the Touch was released yesterday so I downloaded it after installing iTunes 8. Not sure why they need another couple of days for the iPhone... maybe they need to test it a bit more, or maybe they're just trying to distribute server load -- they might not want everyone downloading iTunes 8 and iPod firmware and iPhone firmware and iPod Nano QT movies and iPod Touch QT movies all at the same time.
Genius on iPhone & Touch isn't much to see really... it just shows up as another playlist. Haven't tried it yet.
I can say however that the backup process runs considerably faster now, though I can't say that the overall sync process (of which backup is one part) is any faster. It still takes 5 or so minutes to sync even when no data has changed, which is about 4 minutes and 45 seconds too much.