Looks promising. If time permits (probably not now but maybe in the near future), I would be interested in helping port it to the Android platform (I have an HTC G1 smartphone).
I am pretty sure iPhone apps are written in Objective-C, android development is done in a modified version of Java (the core language elements are the same but the runtime lib is different). I know that android also allows native libraries to be used and loaded (it's linux based so they are just .so that are written in C/C++ and can be loaded from the java application; you can't execute a native binary directly in any way that I know of that's not a console app).
Porting could be an issue here cause there is no real common ground between the two platforms (if iPhone had some kind of native library support you could write a large amount of the game logic in C/C++ and then all the rest involving interaction with the platform would be in the high level language). Of course if other platforms became targets (only ones I can really think of would be palm OS, symbian, and windows mobile; I don't know that there would really be that many users of these platforms) there could be additional porting work involved.
Multiplayer support would be cool. Due to the nature of it running on a mobile device, we would probably need some kind of central server to mediate games (in many cases it might have to relay the data between clients I would imagine). Should this be the case you would be welcome to run such a server here at OPU.
Multiplayer with the original OP2 client would be really cool (though I don't think we know all the details of the network protocol; we know a bit about initiating/joining games and sending messages during a game, not much else I don't think). In addition it would have to play almost exactly the same as the original client so that the game state on both sides would stay in sync.
In any case, keep up the good work, looks pretty cool so far.