Notification Center – Apple has built a brand new notifications system for iOS 5 and this now displays all notifications at the top of the screen even during your games and on the lock screen. By sliding them down you will be able to view them. These notifications include missed calls, voice mail messages and app notifications.
Reminders – this new feature allows users to set different reminders for different times of the day. Using the geolocation support users can configure reminders to sent them a notification at certain times and in certain places.
Enhanced Safari – the iOS 5 browser now looks a lot more like the desktop version with a few extras of its own. Tabbed browsing is exactly the way it looks on Windows and Mac and the new Safari also has the Reader feature and users are able to bookmark content and send it to friends too.
Twitter Integration – the new iOS 5 has Twitter integration and this includes integration with the camera app.
New Mail Client – The iOS mail client has also been given an upgrade in iOS 5 and the app now supports draggable addresses and the ability to flag messages and search for them. You also have a dictionary lookup feature too.
iMessage – this is similar to iChat for iOS users and it allows you to send text messages, photos, videos and hold group conversations. This app also interacts with the notifications app.
Independence From Computers – In previous iOS versions users had to connect to a computer to set them up, update them or synch them. With iOS 5 this ends and users can upgrade their device over the air. There is also a new set up wizard for new devices so you can configure them without a desktop computer.
Lots more small additions – iOS 5 also includes a number of small improvements which includes direct game downloads in the Game Center, a new optional keyboard, Music App enhancements and an enhanced camera app.
If you are a developer and you have an iPhone 4 or 3GS, a 3rd or 4th generation iPod Touch or an iPad you can get iOS 5 from the Apple Developer Center for testing purposes.