Linear positioning

Hello,

ik would like to build somthing like this:
http://users.pandora.be/Ivevanlee/helpme/Untitled-1.html

many off-the-shelf stuff works only straight and I would like to build a
cheap version myself. If there is a good off-the-shelf product I would very
much like to know about it!

Controlling a stepper trough a computer is no problem and I have programming
experience.
Just absolutely no engineering experience :) Can anyone point me in the
right direction or answer questions like:
- is connecting a stepper the right way to go?
- what kind of wheels should I mount on the stepper?
- what kind of rails should I use?
- are any of these components easy to find?

any information you could give me would be welcome!

many thanks,

Ive