If the literal instructions are confusing try watching the YouTube movie:http://www.youtube.com/watch?v=6drMZqmyXQc Also check out the follow up instructions on Stepper Motor Control: Easy Mill Stepper Motor Controller
If you were interested in this project it's likely you have already seen what can be done with an 3 axis(XYZ) computer controlled milling machine. What is suprising is what kind of accuracy you can get out of this thing after you tinker with it a little bit. Make sure all the rails are held firm and straight. Tighten the roller bearings so the stage doesn't shift.
I used it to make PC boards. It's real good for engraving name tags and signs. And it's pretty exciting to see it carve a 3D object out of a block of foam or plastic.
WARNING there's a lot to learn about the software. Some venders offer package deals of motors, drivers, and software. That makes it easier but you pay for it.
I'll add more to this later. Send me comments and questions.