There is one: http://itunes.apple.com/us/app/prince-of-persia-retro/id3739...

The graphics have been updated though, resembling POP2. I wish there was a version or a mode of POP for iOS where I could put it in a kind of "classic" graphics mode that would resemble what I remember of the DOS version I used to have.

Edit: grammar.

There is an Apple IIgs emulator in the App Store called ActiveGS. Out of the box it only runs some pre-packaged demos, but with a little hacking it can be set up to run any Apple II disk image, including games that require multiple disks (it doesn't require Jailbreaking, just USB access to the file system to copy over the disk images and change a config file).

It runs Prince of Persia nicely; I spent the better part of the afternoon playing it. It works so well I haven't even gotten around to playing the "official" iOS version of PoP yet. The experience of holding an Apple II in your hands like that is surprisingly compelling.

Also note that the original Apple II version fits on three 140 kB disks. The iOS version is 60 MB.