A the load screen (the one with the skull, type this case and space sensitive phrase: Roberto Dan R Zaphod B [Space]

After inputting the cheat, press the following to skip to a point in the game.
A - End of first disk
S - End of second disk
D - End of third disk
F - End of fourth disk
E - Go to the Olive In Stein riddle
G - Go to the Let's Make A Real Deal FMV