Upon having breakfast w/ my boys this morning I discovered on the back of their cereal box a comic creator for Honey Nut Cheerios. I have it a shot and found it to be a nice site to use w/ kids to teach them digital storytelling and how to create a comic. Everything that can be found in most online comic creators can be found here: drag-n-drop interface, ability to choose characters and backgrounds, and editing text.
I recommend checking out Honey Nut Cheerios Comic Creator by clicking here.
The only disclaimer I can give is, to unlock extra content you need a special code that you can only get from the back of the cereal boxes.