As you can see on these forums, ports of this game were never done because PC users would always have the advantage of the best control over the game, however the game is under GPL, so I'm sure nobody minds if you port it, I suggest modifing the game so that it would be easier to play on a system such as the psp though. Also, would it be online? Because paintball2 bots really suck, so you'd want to work on that if you were to make it a practical game for singleplayer.