UbuntuVibes: “Ardesia is a free open source application that turns your Linux device into a digital sketchpad. You can make hand drawn annotations, figures, a quick sketch, do some artwork or just use it for fun. Drawings can be made using many pointing devices like a mouse or a pen/finger on your touch screen device.
On the productivity side, this application can be really useful as you can record whatever you are drawing, save it on your system and then share it over a network. Doing live screencasts , demos or on screen presentations is easy as you can stream live whatever you are doing using third party applications like VLC or Icecast. The application is completely free and is under GPLv3 license.
Ardesia needs a composite manager to be able to work and has been tested with Compiz, Kwin, XCompManager (LXDE and Openbox). Also to record your work, you need to have VLC installed on your system. Ardesia provides binary packages for Ubuntu 10.04 and Windows 7.”