This is what you are looking for. I bought a kit just to see what was in it. The styrofoam board is much finer then regular strofoam but I think you can find sheets of it at places like Lowes or Home Depot. It's about 1 1/2 thick and is pink on one side and white on the other. I think Corning makes it. The pattern is drawn on a sheet of red graphite paper that transfers to the foam. You can buy a kit or just the foam board or patterns. It looks great when finished. I put the one I made on the guild secret auction table and it sold above the price of the kit.
Check you PM
http://www.gotscraps.com/fabric-art.htm