Rob,

The points that Jazz makes are very valid ones. Now some points to consider before you even get to the CAM/CNC side of things:

1) What do you plan on doing with the machine? Be detailed in your answer as that WILL greatly effect design/ build of the machine greatly

2) What are your resources? Not just money but also time (learning the hardware/software) and lastly space (which will again affect design)

Answering just those two questions for yourself and write them down so you have it fixed and set where you want to be going with this rather in depth project.

Then get a CAD program. There are free ones and some are okay. For low cost I would suggest ViaCAD2D3D (I own this program and use and I AM a beta tester for their up scale program called Shark FX). Then once you have the feel of that and working with folks on the design side of things, I would look at which controller you plan on using (Mach3, EMC, USBCNC) and get a copy and start reading on the set up and function (yes before you get the machine). Next I would seriously look for CAM program that is within budget and will do what you need (CAMBAM is a good one for 2.5D and there are others). From there you get into the build and the physical learning phase of using the machine and doing. There is a lot of good program to help as well as text books or working with others and learning by experience and finding what works and what doesn't.

I hope this does not turn the temp in the brain pan up to high but better to start on as solid a footing as you can.

Best of Luck and ask as you need to.

Michael