Prezi is a cloud-based presentation software that opens up a new world between whiteboards and slides. The zoomable canvas makes it fun to explore ideas Public Create an account for free. With a public account, your prezis will be publicly viewable, searchable, and reusable.
http://www.boxoftricks.net/2009/05/top-five-online-presentation-tools/
These are five of the best web based applications that allow you to create and share presentations online
Compiled List of The Top Online Presentation Tools and Apps Today On April 27, 2010