At the moment the game is playable, and not too slow. The code can be optimized to make it faster. In the next couple of days I might do that.
Also, regarding the AI code, it can be made better. In one side, the minimax algorithm can try to analyze more moves in advance (only three at the moment), in the other, the board evaluation function can be made better as well.
If you wish to play, go ahead: http://eremita.di.uminho.pt/~ambs/reversi