I have two of those displays, though I havent got a chance to connect them to anything yet (work is keeping me busy). They are "plain" RGB+H/Vsync displays and as someone noted above, 512 colours (3 bit per component R/G/B).
So you will need to feed it RGB signal along with H/V sync with appropriate timings. Since the spec sheet is available and includes all timings, my plan is to get it connected via a PIC or AVR (a faster one mind you) that will generate an output image with perhaps composite video as an input or some other source (maybe internal character generator program inside the PIC/AVR).
Personally, connecting them to the parallel port would be a waste and not too portable, especially when you need a whole computer to drive it. I'm not sure if parallel port can push enough bits to generate the full size image on the display without the use of a frame buffer circuit and what not, so there's more circuitry invovled.
I feel that using an AVR or PIC circuit can replace the frame buffer and parallel port. But that's yet to be done (at least here), perhaps someone else has already done it, thought in all my search of the Web I havent found any similar projects to draw any ideas from.