MTV.com had an interesting interview with id Software's John Carmack. Carmack discussed their plans for iPhone projects and revealed that they are working on bringing their classic games to the iPhone:
But literally before I came in on this interview, I was going around poking with some of our old titles. I’m really looking forward to bringing over an id classics line — start with “Wolfenstein 3D” and go through “Doom” and “Quake” and bring pretty much all of them over to the iPhone because I’m a really big booster of the platform. And it frustrates me to no end that here we are without product yet shipping in the iPhone. We’ve had a couple of thwarted attempts at different things. I’m frustrated about it and trying to do something about it. [laughs]
Carmack notes that they have Quake III already up and running on the iPhone.
Aside from these classic games, Carmack discusses their plans to bring Wolfenstein RPG to the iPhone though he admits its not a "designed-from-the-ground-up-for-the-iPhone game".
For that, they have another title that they are working on using some existing id assets and is described as "graphically impressive". No official release date just yet.