newbie - pcb type machine

hello, i am new to all of this, and i want to build my own CNC machine
for making prototypes, parts and quick PCB's for my robotics projects.
I have been researching for a while now, and i think i am ready to
begin. I have some old dot matrix printers i have taken mostly apart,
and i can't find much (if any) info on the stepper motors i got from
them, but i think i know what i got, and i think they are ok for my
needs. I'm not looking to build a big machine, like i have seen on
many members' websites, I just need like a max of 12"x12" XY table and
probably just a 1" Z axis.

Since i am such a beginner, i would like to know that since i am not
looking for really, really precise measurements, what is better to use
as a building material, metal or wood?

Also, i don't feel like programing any chips for my interface, so what
programs (preferably free) should i use for my machine? (I use
eaglecad for PCB's. and i am planning on using one of the TTL
interfaces i've seen online.)

Thanx,
Adam