Joe,
You'll be calling it "Plug & Play" if you carry on like this! Exactly what most of your readers require, thankyou.

I haven't got as far as mutilating my webcam just yet, the B&D laser beastie is many years old and is specifically designed to hang on a wall and produce a straight horizontal and vertical line along the same wall it's hung on rather than a horizontal line across the room. Laser units are cheap on eBay, it's just a matter of working out which ones to buy and how to mount them.
I've yet to decide exactly how I'm going to use your program, with a laser or with John's sugestion using the image of a taught wire, or with both at different stages of setting up the whole machine. More thinking and experimenting is required to devise a method of aligning all the different parts of the machine in isolation and in the correct order to end up with a hand built machine that can cut out pieces with a much higher accuracy than the basic methods used to construct it.

Kit