Encours.org is a teleconferencing system that works directly in your Web browser. It has shared slides that are visible to all, an integrated audio system with recording, "laser" pointers for lecturers, video replays of the presentation, and a chat interface with the audience. It can be connected to a phone server.
Aspose.Slides for Java is a Java component for manipulating PowerPoint presentations. It doesn't require PowerPoint and supports export to PDF, embedding and linking of audio and video frames, slide cloning, thumbnail generation, and presentation features, the ability to extract text from a presentation, and more.
Presentation is a standards-based presentation platform in the style of S5 and Opera Show Format (both of whose file formats are supported). It provides an easy way of writing (in HTML or XHTML) a portable presentation that can easily be read from a standard Web browser. In addition to what was offered by S5, it adds support for CSS3 transitions.