Geogebra is a free and open source geometry program, similar in function to Geometer's sketchpad. It also allows for exporting your work to a web friendly format.
This coming Wednesday March 25th, either between 7am to 10am or 1pm to 5pm I plan on running an online workshop on how to use Geogebra. This will have to be limited to the first 20 participants as I am using the free online and screen-sharing website, http://dimdim.com
(which has a limit of 20 people for free meetings).
Sign up here: