I know a lot of people are disappointed that Facebook 3.0 does not support push notifications, including me. There is a workaround if you use Prowl for iPhone. A new app has been released that will work with Facebook called Growlbook. I tested it and it seems to work just fine. I also use Prowl to get my Gmail and work email notifications. Of course the drawback with any Growl/Prowl solution is that a PC must be always on.