A guy from Everything Digital used a program called Telekinesis to run World of Warcraft on his iPhone!
After having finally gotten an iPhone yesterday after much hassle in tracking one down, I discovered Telekinesis, a wonderful app that runs on your Mac and provides a web gateway for controlling it through an iPhone-friendly interface.
Naturally, I tried running a variety of applications using my iPhone as a controller and screen for my Mac, but the most impressive was World of Warcraft. While performance was hardly smooth, I could control several actions in WoW through the iPhone interface. Most notably, I could read and respond to in-game chat without too much of a problem.