Things which I intend to do in the next release:

Pawn promotion - the code is in the engine, but I need to
make a window pop up and prompt the user to choose which
piece they want. At the moment, it defaults to queen.

Configurable Time/Depth - at the moment they are hard-coded,
although it wouldn't be too difficult to read these from a 
configuration file at startup.

Ability to save/restore games.

Ability to start a new game without killing/closing the window.

Undo feature - the code is in the chess engine, I need to
implement a button on the UI for it though.

If the computer is playing white, swap the pieces so black is at
the bottom.