Flowgram is a total online multimedia presentation tool.
Think Powerpoint with voiceover, interactive webpages, photos and more. Ideal for online conferences and even better for archiving conference sessions, Flowgram is almost as good as being there.
Here is a Flowgram on Web 2.0 by mseifman:
Although it can be a little clunky to use, the benefits of Flowgram far outweigh the drawbacks.