You could also try the Hera marker--it really does not mark, but you press a point on the fabric and "draw" with it. It leaves a visible crease which you then follow as you quilt it. There is a slim one (
http://www.amazon.com/Clover-4002-He...ds=hera+marker) to be used for intricate designs and a larger one for more basic designs (
http://www.amazon.com/Clover-490-NV-...ds=hera+marker.) You can find these at Joann's, quilt shops, or online.