http://www.geom.umn.edu/apps/quasitiler/start.html
This site presents a research project at the Geometry Center of the University of Minnesota. QuasiTiler draws Penrose tilings and their generalizations. Here you will find mathematical explanation of the complexities of Penrose tilings and discussion of how the QuasiTiler works. If you get the itch you can also just jump in and start creating. The images are fun, and the instructions will easily take you through the process.