Tux Paint is a free, award-winning drawing program for children ages 3 to 12. Tux Paint is used in schools around the world as a computer literacy drawing activity.
It combines an easy-to-use interface, fun sound effects, and an encouraging cartoon mascot who guides children as they use the program.
We love using it up on the Interactive Whiteboard and it is a great tools for emerging guided writing, where the children get to create a story. Tux Paint is free, Open Source software, distributed under the terms of the GNU General Public License.
Find the download link here: http://www.tuxpaint.org/download/