Usually the first problem I find with teaching children to draw is getting them to hold a pencil correctly.
As a child before the war we had to spend hours doing copper-plate script to write neatly. It was boring, but you could read most children's writing. Not so today with biro's and word processors.
I always say "Hold your pen like a dart", but though that is typical for animation, Fine-artists use different methods. One method I came across is at http://thegluckmethod.com/html/freelesson/index.html which is worth looking at.
You don't need to be able to draw to animate though. Take a look at:
www-ui.is.s.u-tokyo.ac.jp/~takeo/java/smoothteddy/index.html (just type in 'smooth teddy' to get listings) to see the trend in simple animation. This appears not to be a commercial program yet, but it will be fun for kids when it is.
Another similar 'instant' animation program beingdeveloped is http://www.k-sketch.org/
This could really take off in schools when it's available.
This trend will bring back the Light-pen as an input device. They were common in the 1960s but went out of fashion when the mouse and drawing tablet became available.
Another recent development yet to hit the shops is a screen that is so thin and flexible it can be rolled up. This would be suitable for a cheap light-box/monitor when it's available.
Then there is Googles own drawing program at http://sketchup.google.com/product_suf.html
It does 3D geometric shapes but easy to use.
It will be interesting to see if a killer-application comes these instant animation programs as there is no doubt that there is a great need for a graphical language that overcomes the barriers of the spoken and written ones.
Look at: Drawing Techniques