Air Display is an iOS app that lets you use an iPhone, iPod touch, or iPad as a secondary display for a Mac. This week the developer added support for the new iPad’s Retina display, which means that you can use Apple’s new tablet as a 2048 x 1536 pixel Mac screen.
You’ll need OS X 10.6 Lion or later in order to take full advantage of the new Retina display. You can do this by turning on HiDPI mode to render graphic elements at twice the normal resolution. This keeps text, images, and other items from looking really, really tiny (or blurry) on the iPad screen.
The app also works with Windows computers, but since Windows doesn’t have a HiDPI mode you won’t get the full benefit of the new iPad’s high resolution display. Instead you can use the app without Retina support to treat the latest iPad as if it had a 1024 x 768 pixel display.
Air Display is available from the App Store for $9.99.
There’s also an Android version available from the Google Play Store for $9.99.