According to this post on Daring Fireball a new iPhone SDK Agreement release in conjunction with the iPhone OS 4.0 announcement today specifically bans any iPhone appli
A policy against transpilers and interpreters was in effect from April 2010 through September 2010. It is no longer in effect, though bans on hot-patching and third-party JIT engines remain in effect. From "Apple relaxing SDK license agreement: MonoTouch (and Flash?) officially allowed":
In particular, we are relaxing all restrictions on the development tools used to create iOS apps, as long as the resulting apps do not download any code.