Animoto is easy to use and a lot of fun! You can upload photos and video, and the app puts them together in a kaleidoscope of shapes and forms. You can also add music from your desktop or purchase something from iTunes. Once the video is completed, you can edit it, and share via email or embedding your blog or Website, as I have done here:
The free version of this editing tool is only 30 seconds long (about 12 photos). For $3 US you can upgrade to an any length video, or for $30, you can make any length videos for a year. Ronaldo Lima's school uses the latter option, and students use Animoto extensively as a way of publishing their projects.
To use the program, students would take and select photos and video of their project, arrange and upload the shots, and select appropriate music. (There is very little writing involved, unlike other programs where there might be titling on each photo.) I believe students could, however, create a desktop recording (e.g., with Audacity) describing the photos as they flash by, and use that file instead of the "music" accompaniment. For an additional $5 per video, you can make a higher resolution or MPG4 version that can be downloaded and/or burned to a DVD.
Thanks to Ronaldo Lima of the Webheads for mentioning this app.