If there is one drawing book that I see consistently on homeschool curriculum sites, it's Drawing with Children by Mona Brookes. I am not anything of an artist myself, so I thought this would be a good one for me to check out. When it came in the mail, I pretty much sat down and read it cover to cover. It is a wonderful resource for any teacher (or mom!) who is going to be instructing children in drawing.
It talks about setting the stage for drawing, having the right attitude, and what kind of materials to use. The biggest point of the book is teaching children to not look at whole pictures (because that would be very daunting!), but to look at each individual type of line that makes up the picture. Drawing is nothing more than putting lots of small lines/shapes together.
Drawn by my 5 year old