I am new to this stuff and getting a CNC retrofit for my bench mill. What is the terminology of CAM? What does it do? I know I need it to run my mill but how does it work and how can I teach myself to use it? I have been told to get several different programs (all expensive, IE: Master Cam, Gibbs Cam, etc). What exactly am I going to need to get right away and what is optional? I know I'm getting a stepper motor system but what controller etc, I don't know, I will find out within the next month as the parts come in. Any help would be greatly appreciated.

Here is a few very basic things to look at http://www.cnczone.com/forums/forumdisplay.php?f=172