Animoto

At Animoto you can upload pictures or Powerpoint slides, add music from Animoto or your own, and create a video slideshow. I have made numerous book trailers at this site, as well as short clips for the morning announcements. They have a wide assortment of music to enhance your slide show. If you give your students an assignment that requires the use of the standards that pertain to using available technologies, creating an Animoto presentation would be an effective product that meets the standards.

http://animoto.com/

Here is an example of an animoto video that was made for HJH.
http://animoto.com/play/aXqTVm0tXz4CwiBEEOraGg