It’s nice to see Apple has finally updated the app, so that the UI is optimized of the iPad. The previous version would work on the iPad but only with double pixels or with the iPhone UI. The remote software needs to be paired with your iTunes library by entering the 4-digit code into iTunes that is displayed when the app is opened.
The app will also control Apple TV, since the new Apple TV starting shipping yesterday, this update probably has more to do with Apple TV than the iPad. The app and others should make the iPad a perfect companion to the new Apple TV.
• Control iTunes and Apple TV, from anywhere in your home
• Pause, rewind, fast forward, shuffle, and adjust the volume from your iPhone, iPod touch, or iPad
• View album, movie, and TV show artwork
• Create and update Genius playlists
• Create and edit playlists in iTunes
• Search your entire iTunes library
• Control iTunes to send music to AirPlay speakers
• Control the volume on each speaker independently
• Control Apple TV with simple finger gestures
• Enter text with the keyboard
• Even control Shared Libraries on iTunes and the new Apple TV