How to convert a Powerpoint Presentation(.ppt) to a HTML5 presentation?

I don't think there is an "easy" way per sé to do this. However, you could probably try to build some template and copy and paste the exported-to-HTML content into it.

From a first glance, that's the answer. Some further step would be automating it, but does it worth to do?
--SA

Very good point unless you want to take adv of PowerPoint to build the presentation, depending on how it looks when its exported. Would be nice if they could export it in XML, and you can just build the presentation on the fly with JavaScript or something like that.