It's been nearly 10 years since I first came across plans for a LED output device using the parallel port of a PC. That first program was portato, which still can be found out there on the old sunsite.unc.edu.
This is my slightly different interpretation of what my computer should tell me through the visual medium of light and movement. The PC parallel port has 8 data lines, each of which is a 5V TTL output. My software simply toggles those data lines on and off in a prescribed pattern.
The hardware is simple. Here's the scoop: Pins 2-9 are the data lines. 18-25 are signal ground. So, get yourself an old printer cable, 8 LED's, 8 150k ohm resistors, and a breadboard.
Any questions? Comments? Suggestions? Email me at jeremy@worrells.org. I'll do what I can to help.