Mixbook - Create online books with text and pictures. Different from Storybird in that the composer chooses the pictures.
Storybird - Collaborative storytelling. Match stories with artwork. Students can join a class without divulging personal info.
iBooks Creator - iPad app. Costs $4.99 but well worth it. Very usable at all grade levels. Imagine your students on a field trip with their iPads taking photos and usingthem to create a book about the experience.
Story Buddy - the lite version is free. We like this story creator because you can save the final product as a PDF book and send it anywhere!!
Bookemon - create online books.
Demibooks - book writing app for your iPad.
Little Bird Tales - create books for the very young. Uses student voice. Doesn't require writing. Great site for early childhood.
GoAnimate - Animation site. Create stories with animation characters.
DomoGoAnimate - A school friendlly version of GoAnimate which all inappropriate content is filtered out. You can create animations that can be embedded onto blogs, wikis, etc.