I'm now a happy cell phone IF player too. Specially delightful on the bus...
For now, just using Zippy for Motorola Milestone 2 Android. Although it comes with a sliding tiny physical keyboard, I'm now very fond of the Swype touchscreen text input method. amazing!
Parchment works too, but CSS for mobile should be fixed a bit -- perhaps slightly larger spacing in the borders...
Hope Tads and Glulx follow along. I wonder about Inform 7 too: it seems most people like it more to write than to play IF! Writing IF on the go, can you imagine it?
Really, a little time with current generation mobile hardware is enough to convince anyone that desktops will be pretty much dead among the general, mostly consuming populace in the very near future. Only software developers and hard typing jobs will actually require desktop workstations. and die-hard PC gamers who don't like fixed-hardware consoles.