As far as software, you can't go wrong with Mach 2/3 as your machine driver for the money. For producing your gcode specifically for plasma, visit the Sheetcam forum here and on Yahoo (and the sheetcam website). You can download a copy and get a free trial registration. Again, for the price you can't beat it and it's specifically set up for plasma. It'll automatically add lead-in/outs etc and is very user friendly and easy to learn. Sheetcam will import dxfs, and others, so corel is a low cost alternative if you don't have autocad or another cad drawing program. Quite a few folks use the corel and sheetcam combo and produce some great stuff quickly and efficiently.