StoryJumper is a free web-based digital storytelling application that includes a free classroom edition for managing multiple student submissions. Registration is easy and prompts users to not use real names (though dates of birth are required). Uploaded content may be set to public or private. Users may choose artwork from an existing gallery, upload their own photos or scanned artwork, and write all the text. Recommended for grades 1-5.
Read a review on the Graphite site here.
StoryKit is a free digital storytelling app for iPhone, iPad, or iPod Touch that was produced by the creators of the International Children's Digital Library. Users add images by taking photos or choosing photos from their device's image library, and can add text and narration. Finished stories are saved inside the app and on StoryKit's server. Stories can also be emailed to share with others.
An educator-focused review of StoryKit can be found here.