Programming 2 Stepper Motors to Make Art

Programming 2 stepper motors to make Art Hello guys and girls, really after some advice from you remarkably intelligent and helpful people.

I want to make a Robot that can draw! (have had this in my mind ever since i first saw the Ardino, and goggle "microcontroller" for the first time and tentatively started asking questions)

so this is where Im up to...I have constructed a rig with two 4 pin Bipolar Stepper Motors as bellow

and have it mounted like this:

NOW......this is where you wonderful people come in.........where do I go from here????

what I have been thinking is some way to use a plotter driver to process the image>serial>Arduino>stepper motor = Image!

But I'm quite clueless, so any suggestions with nice basic explanation would b amazing. :-*