FreeDesktop

It is a desktop drawing tool that can help you to lock your desktop, draw a line on it or set the line's color or width.

You can as well clear the points (lines) that you have already drawn or save the drawings you have created. The tool can be used in education, for doodling or, for example, when you try to explain something to someone.
The application is compatible with Windows95/98/2000/NT/Me/XP.