• Updating your iOS device
    iTunes can update your device to the latest available iOS software. An update doesn't affect your user content or settings. iTunes creates a backup of your iOS device and then performs the update. Follow these steps to update your device:
    1. Verify that you are using the latest version of iTunes before attempting to update.
    2. Connect your iOS device to your computer.
    3. Select your iOS device when it appears in iTunes under Devices.
    4. Select the Summary tab.
    5. Click "Check for Update"
    http://support.apple.com/kb/HT1414

Last Modified on March 9, 2012