National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Graphing an Ellipse
Dr. Math, in a reply to a student question, mentions a couple of different methods to use to obtain the graph of an ellipse, the doctor details one way by using the known coordinates of a circle.
University of Illinois
University of Illinois Urbana Champaign: Chickscope Egg Math: The Shape of an Egg
Drawing a perfect ellipse with pins and string is demonstrated with a java simulation.