This tool has the potential to allow more freedom in classroom instruction than your standard presentation tools like PowerPoint of Keynote. Through a non-linear approach Prezi could help foster more open discussion and better engage your students.

Here is more info from their Website:

Prezi is zooming sketches on a digital napkin.

It’s visualization and storytelling without slides. Your ideas live on stage and on the web.

Have you ever wondered about presenting your thoughts as free as they come? Ever got tired of creating a slide show? It’s been said, that the best innovations come from people who are unhappy with the tools they use. We realized that our ideas won’t fit into slides anymore. Putting together creative thinking and technology expertise, we have created Prezi, a living presentation tool.

http://prezi.com/