Airplay uses more of the tv screen so many games will display as full screen or close to it. Some games will use the ipad as a display screen like real racing 2 does with a huge map on it instead of displaying the game. The tv is also full screen.
So far, I just got my hdmi converter which supports airplay too, I have noticed the following games, will try to keep it current.
Real Racing 2
Modern combat 3+4
Sky Gamblers - Rise Of Glory
Ducati Challenge HD
Touch tanks 2
Airplay is totally awesome, lets me play my ipad as a console. Some of the later titles I added from previous posts, so if there are errors or omissions, please post and I will add them to this list.
We have release 'Sparkling Poker' last week, which uses the iPad as a virtual game table while each player plays with his/her iOS device. It works with bluetooth, so there is no need for an internet connection after you downloaded the app on your devices. You can play with up to 5 players simultaneously.
As the game is only presented on the iPad, and there is no interaction, playing cards this way is ideal for Airplay. It is free (you only pay for chips if you run out during a game and want to stay in), so just download it on all devices you have available and you are good to go!