When iOS 6 was released, YouTube disappeared from Apple's official app list. To fill the void, Google released a version for iPhone but not for iPad. That has been remedied today with a new iPad-friendly YouTube app which also adds a few new features.
In addition to support for the iPad, Google has optimised the YouTube app for the iPhone 5's larger screen. The app also now allows you to stream videos via AirPlay, add and remove videos from your playlist, and actually get a response when tapping a link in the video description.
YouTube [iTunes App Store]