I built a CNC machine recently and one of the first things to do is of course to improve it. I used fritzing (http://fritzing.org/) to draw my circuit. When I was done I realized that I had no software at hand, that could make g-code from the exported gerber files. After some research I found:
- visolate (http://sourceforge.net/projects/visolate/) for milling the traces
- drill2gcode (http://fablabamersfoort.nl/drill2gcode/) for drilling the hole
I managed to produce a one layered pcb that now drives my CNC machine.