I stumbled upon this tonight. It's the development diary of John Carmack for his work on iPhone Wolf3d. Here is a little excerpt:

"Wolfenstein was originally written in Borland C and TASM for DOS, but I
had open sourced the code long ago, and there were several projects
that had updated the original code to work on OpenGL and modern
operating systems. After a little looking around, I found Wolf3D Redux
at http://wolf3dredux.sourceforge.net/. One of the development
comments about "removal of the gangrenous 16 bit code" made me smile.""

"I sent an email to the Wolf 3D Redux project maintainer to see if he
might be interested in working on an iPhone project with us, but it had
been over a year since the last update, and he must have moved on to
other things. I thought about it a bit, and decided that I would go
ahead and do the project myself."

Sheesh. Too bad John didn't send me an email. "Um, sure John, I guess I could find the time to help you work on Wolf3d for the iPhone." That would of probably been my response.

Anyway, it's a pretty cool diary by John. I have since downloaded the source code. I don't own an iPhone but I have been interested in making some sort of app for it. Why not a Wolf3d mod??