Press and hold <Ctrl>-<Shift>-<Q>-<W> in the Main Menu. Then release <W>
and you get a Mission Select Screen.
During the Game, press and hold <Ctrl>-<Left>-<Shift>-<X>-<S>. Release <S>
and press then RAGGSDALE (while holding the other buttons). You receive a
list now with more cheats.
During the game, enter CHEATS to make your units stronger and disable the
fog of war.