Synthetic LLC, developers of Hipstamatic as well as IncrediBooth have been busy updating this app. It has now been optimized for the iPad retina display and also offers support shooting with the rear facing camera.
IncrediBooth is a very fun app and incredibly popular. This is a free update if you have previously purchased this app, if not you can download it here. It retails for $0.99/£0.69/download