One of my ongoing projects has been building my own CNC routing machine.
It's a great tool have for making PC Boards and custom parts.
It's also a great way to make yourself crazy!

Klunk CNC Mini CNC Controllers Links
My original attampt to build my own machine.
Built from printer parts and hardware store components.
The build is photo documented. I used a different parts configuration for each axis
I built this mini-cnc in two days in an attempt to drag it to the Maker Faire.
It's made from Sam's Club cutting boards, 1/4" all thread, 1/4" rod and machine screws.
Control Circuits:
This is a classic Unipolar controller built from UCN5804Bs. It's very, very economical at $22 in parts.
I also designed a bipolar stepper controller, but the part count is very high.
Samples offset the costs, but I prefer the unipolar design for simplicity.
I used microstep boards to build the controller for my mini-mill. These are well designed, cheap to build and support microstepping.
K-Cam is great for testing with a windows box. Once you know it works, check out something realtime like
EMC Linux There's a brain dead install that's (relatively) easy to setup. You can run the interface remotely too.