At Macworld today, I got a chance to speak with a MacBook product manager at Apple about the new external USB SuperDrive. I was wondering if it could be used with regular Macs (like my 24" iMac), but I was told that it wouldn't be compatible. While the drive is apparently a standard small form-factor DVD burner, with a standard USB 2.0 connection, it requires a special driver that only ships with the MacBook Air. While it's possible that said driver could be extracted from the MacBook Air and injected to a Leopard install on a different machine - I'm not sure that it would be worth the hacking. There are probably easier, more sanctioned ways to add a second optical drive to an iMac.
-Andy.