I just discovered Bitstrips. I think I read about it on BoingBoing. I'm not sure how I'd use it in education, but it is fun. Basically you create characters by choosing from a menu of features, or you can use characters that other people have already created. It's kind of like creating a Mii.
Once you have your cast you drop them into a comic strip and give them something to say. You can change their poses and expressions as you go. There is also a limited number of props available to help flesh out your strips. You can also make your stips/characters available for other people to use or re-edit allowing for a collaborative effort.
So far I've just been having fun reenacting some of my morning conversations with our new librarian who usually has a new idea for how we can revolutionize education in our building every day or so.