Not yet, out on the 12th isnt it. My friend has it as he is a dev, but not had a chance to look at it.
What do you think, seems to borrow from othe os, notification bar from android, iphone messages from crackberry
Notifications was something that I really liked on Android (though I think Android copied it from WebOS), but apple have combined it with their push system to create a very elegant information feed system. I'm very pleased with this feature!
Yes, the iMessage is taken directly from other IM systems (though it is transparently handled with your texts), really it was a missing feature of the old versions of the OS rather than a great new feature of iOS5
