Upload pictures, select music, and let animoto put together a very cool slideshow. A free account let's you create a 30 second presentation. Full length videos require a subscription. Here's a quote from their "about us" page:
Animoto Productions is a bunch of techies and film/tv producers who decided to lock themselves in a room together and nerd out.
Their first release is Animoto, a web application that automatically generates professionally produced videos using their own patent-pending technology and high-end motion design. Each video is a fully customized orchestration of user-selected images and music. Produced on a widescreen format, Animoto videos have the visual energy of a music video and the emotional impact of a movie trailer.