The features to be introduced to be announced at iOS 5 are not official yet.However,it is being expected that iOS 5 will bring revamped push notification system.
Earlier there were reports that iOS 5 will get Lion Style Dashboard Notification System.
Now,there is a new Slideshow style iOS 5 concept.
The Slideshow presents all the features expected of iOS 5.There are 97 slides to watch for.
View the Slideshow presentation concept of iOS 5
Slideshow presentation concept of iOS 5