There are quite a few lines concerning the status of the MAME port to iPhones. There is still no download.

CURRENT STATUS: Can definitely be made playable by choosing a suitably old version of MAME. Tested with version 0.29 since the code was simple enough back then to slap together something quickly to test performance. I am going to arbitrarily target whatever version runs the Galaga ROM I have on my arcade machine. I suppose I should start thinking about how I want to do the configurable control system. In addition to the straightforward “this area of the screen is this button/joystick/trackball/dial” controls, I’d like to support gesture based inputs as well. Imagine playing Tempest by making an actual circular motion on the touch-screen, or tapping anywhere to fire, or gesturing left-right up-down to move the joystick. You could play Pacman without any screen real estate wasted by displaying controls. I should be able to actually put some time into this over the weekend while I’m on vacation.