How Do I Use AirPlay With My iPad And Apple TV?
Before using AirPlay, make sure your iPad (or other iOS device like an iPhone or iPod touch) has iOS 5 installed. You should also update to iOS 5 on the Apple TV.
From there, using AirPlay to mirror your iPad to the Apple TV is pretty straightforward. When you're in an AirPlay compatible app like Videos, just start playing a video. You'll notice an icon that looks like a rectangle with an arrow pointing up inside it. Click on that icon and an AirPlay menu will appear. Select Apple TV to begin streaming from your iPad to the Apple TV.