To make sure you can run the latest and greatest iPad apps and get the hottest new iPad features, it's a good idea to update right now (and periodically) to the latest iPad operating system (iOS). Here's how to update your iPad's iOS:
Plug the 30-pin end of the Dock Connector to USB Cable into your iPad and plug the USB end into your computer.
The iPad will charge itself when connected to a computer, so if you’re updating the iOS from a laptop, plug it in so the battery doesn’t drain before the update is complete.
Click your iPad name in the Source List, and then click the Summary tab if it's not already displayed.
When iTunes opens on your computer, the Devices section appears on the left side of the screen. That’s where you find the Source List.
Read the note next to the Check for Update button to see whether your iOS is up-to-date. If it isn't, click the Check for Update button.
iTunes checks to find the latest iOS version and walks you through the updating procedure.