This is a very good question, one I've thought about for a while but never been able to put enough time (or thought) into the subject; though it'd be really great if we (the MK Community) invested enough time into it to where we could make some really decent projects out of it.

Here's a tutorial based on doing the parallax floors in Capcom; maybe you'll make some sense of this:

http://www.newwavemugen.com/Dev/index28.php.htm

Good luck!

I saw that, but the meat of it seemed to be at http://www.shinmugen.net/winane/ShadowDragon-X4_parallax.zip
Unfortunately, that link gives a 404. I don't suppose anyone has this tutorial somewhere?