Boston University
Bu: How Does a Satellite Stay in Orbit
This site contains a lesson on the ellipse. The lesson has students draw an ellipse with pencil and string, and discussions on orbits and theoretical orbiting situations.
Other
Xah Lee's Home Page: Ellipse
Good site with history, descriptions, properties, etc. of the Ellipse. This site gives the parmetric equation of an elipse and many interesting ways to find an ellipse in objects.