thumbstacks

Thumbstacks is a bare bones but functional application that allows users to build presentations online and present them via a permanent URL, using both Flash and Ajax. The site includes sample presentations

Features include an online interface to create applications, the ability to manipulate fonts (including sizes and colors), drag and drop functionality, image inclusion (including flickr images), with more features to come. Something to challenge your students with as they share and present work, and yet another online application to join the likes of online collaborative word processor writely, and online collaborative spreadsheet tracker.