Though the latest version of iOS for iPad, iPhone and iPod Touch devices won’t land until this fall, a number of its new outstanding features were revealed at the 2011 annual Worldwide Developers Conference (WWDC) by Apple including Notification Center, iMessage, Newsstand, PC-Free, Safari Updates, Deep Twitter Integration, Reminders App.
The iOS 5 is compatible with iPhone 4, iPhone 3GS, iPad 2, iPad, and iPod Touch (3rd and 4th generations only). According to Apple, however, some of the new iOS 5 features may not be available on every compatible device.
Now, let's take a look at new outstanding features of Apple iOS 5 in pictures.
Notification Center

In iOS 5, all your app notifications are put in one place. Let's slide down from the top of any screen to see the new Notification Center, which is also in your iOS device's lock screen for easy access
iMessage

iMessage is a new SMS messaging feature for all iOS 5 users, allowing you to send not only unlimited text messages but also photos, videos, contact files and location data via Wi-Fi or 3G to any other iOS 5 user
Newsstand

The Newsstand that looks very similar to iBooks – an Apple’s e-books app is a new folder, where all your iOS-based newspapers and magazines are put into. If you subscribe to a particular magazine your subscription automatically updates in the background via Newsstand
PC-Free

The cord between your iPhone, iPad, iPod Touch and your Mac or PC is being cutting by Apple, which means you can buy any iOS mobile device and start using it straight out of the box without activating it via iTunes. Besides, you can download iOS software updates straight to your device
Safari Updates

Safari on iOS 5 adds tabbed browsing for the iPad, and all iOS devices get a new version of Apple's Instapaper clone, Reader, which feature strips out ads and other content from web pages to let you read text in a clean, simple interface. In addition, the Reading List syncing across all your devices via iCloud helps you store a list of items you want to read later
Deep Twitter Integration

With deep Twitter integration in iOS 5, the social networking site gets easier on the iPhone because the new Twitter feature offers users one-touch functionality to tweet links to photos, web pages, YouTube videos, and Maps. What you must do to activate Twitter in iOS is to sign once in the Settings app
Reminders App

The Reminders App is a built-in To Do list, allowing you to store due dates and location data. When you are near the store next time, your GPS-enabled iOS device will alert you
Faster Camera

Only by double-clicking the home button, even if you have a passcode set, the new camera app in iOS 5 will be quickly and easily accessible from the lock screen. The new camera app boasts grid lines, pinch-to-zoom, and auto-exposure and auto-focus locks to help you move the camera angle without losing your focus point

A rich text support in the Mail app for iOS 5 added by Apple has some outstanding features such as bold, italics, underline, and indentation controls. iOS 5 also brings full message body search to Mail instead of just search for subject lines and addressees
Game Center

With Game Center in iOS 5, users can add a profile picture to your Game Center profile and find new Game Center-enabled games within the app. They can also find more friends by viewing friends of friends and recommended friends
Apple iOS 5: Top Ten New Outstanding Features
Related links:
Apple WWDC 2011: Urgent Preparation
Apple iOS 5: Top Ten New Outstanding Features