There are view apps out right now that support video steaming over AirPlay. It just got released to the general public last week and developers ares till getting all the code added, I hope. I want to see all video/audio apps use airplay.
I am the developer of the "Film Study" iPad app and it does support AirPlay. When playing a movie the controls have AirPlay button to the far right that allows you to send the audio / video to appleTV 2 only