I just downloaded the iPod touch version of the X-plane 9. I am quite impressed about it. It is by far the best mobile game I have ever tried. The controls are done with the accelerometers and throttle and flaps are controlled with two simple finger usable sliders on the screen. The landing gear and brakes have translucent buttons on the bottom of the screen. Everything is fully finger usable as it should.
The aircraft selection consists of Cirrus Vision Jet, Piaggio Avanti, Columbia 400 (that was a positive surprise since it wasn't included with X-plane before), and the C172SP. Needless to say that the Cirrus Jet is the most fun of these to fly.
It is possible to set the weather to IMC, but because the instrument panel does not fit into the tiny screen, it is not included with the sim. Therefore flying IFR approaches with the iPod version is not possible. You can keep the attitude though inside a cloud because of the HUD that includes attitude indicator.
Anyway, this is the best iPod touch app you can find from the App store. It only costs 7.99 eur and is worth every cent. You can find it under games category.
What could be cooler than fly virtual Cirrus Jet in bus when going to work tomorrow?!