TapATalk works (for a fee) but soon here I'll have the code in the box to publish one myself.
I'm also planning to get things up on BlackBerry as the TapATalk 'Alpha' is even less usable than the browser.... which on a BlackBerry is truely sad.
I could be talked into an iPhone version after the Android one is in the can, but I have to port the core over to Objective C, so that could take a bit. Still, half of the issue with the lack of other software is that the API is in rough shape. Its a long hard slog.