Sketchpad is a site I just read about on Free Technology 4 Teachers. This is a place where people can draw/paint online. It reminds me of a cross between Alpoy and Paint Brush, and is an excellent alternative to both. What I like so much about Sketchpad is how easy it is to use. Plus, w/ all the editing tools available for the user it really is one of the better free drawing applications out there.
Give Sketchpad a try by clicking here.