Jerry's Artarama - Free Video Art Lessons from the World of Art are aimed at children who want to explore their artistic side and just have fun!
Kinder Art - An award-winning art education website for parents, teachers and children of all ages. KinderArt® features free art lesson plans.
Origami Player - Origami folding

Psykopaint - Create a full digital painting online. This includes plenty of filters and tools to play with. Also upload your own photographs and enjoy creating cool digital images from them. 

Snowflake Creator - 3d snowflake creator. 

KerpoofChildren can create their own animated story boards, drawings, movies, and more. Follow the lesson plans to learn how it all works. 

Make Believe Comix - Kids can create their own comic books and manipulate the character emotions. Lessons are also available under How to Play. 

Jackson Pollock Painting Creator - Create your very own Jackson Pollock style painting by dragging your mouse cursor.

Wiiplayable - This online sketchpad may be played on the Nintendo Wii if it is connected to the internet. Just go to the same link in your Wii, and use the Wii remote for the controls instead of the mouse. The Wii is not just for video games! 

Art Express - This site is designed for kids between grades 1 and 5. Sections include educational art lessons to help children learn how to paint and draw, including exercises on composition, design, color mixing, drawing, and much more. 

Paper Critters - This is a fun online origami creator for kids. Click on Toy Creator, then start playing with this cool origami tool. When finished click Preview to see your creation in full 3D.