Update your iDevices to iOS 5

First off you will need to update your iTunes to version 10.5 to upgrade to iOS 5. The upgradable devices are iPhone 3GS, iPhone 4, both iPad's and the 3rd and 4th generation iPod touch.
The new iOS brings the following features:

• Camera access from the lock screen
• Pull down notifications
• Twitter integration
• iMessage & iCloud
• News-stand & reminders

Unfortunately the voice assistant "Siri" is restricted to the new device the 4S.
Happy Updating!