From the 'Things I get sent' file:
"Go back in time and unleash your creativity. Visual Typewriter lets you write using a virtual typewriter from the 20th century and enjoy an original and inspiring writing experience."
http://www.nolad.com/vt/index.php (Windows-only, I'm afraid. No idea if it does key jams, ribbon twists, or features virtual strips of Tippex-coated paper for those special error moments...)