The app is actually a scaled down version of the new Special Edition version that was released for PC and Xbox Live recently, so it looks fantastic. Early reviews on the app store say that the pointing controls need a bit of work, but who cares! It's Monkey Island on the iPhone!
My only concern is that it costs $10. Which wouldn't necessarily be too much to pay, except for the fact that I just forked out for the game on Xbox Live last week. As much as I love Monkey Island, I don't think I love it enough to buy it twice over the course of a fortnight.
But still – here's hoping that LucasArts jumps on this big time and starts releasing all the old SCUMM games officially. I've got a hankerin' for some Day of the Tentacle!