Amit at Digital Inspiration has a great comparison of the following tools, all of which can be used to host PowerPoint presentations online: Zoho Show, SlideShare, Scribd, SlideAware, and Splashcast. You can also skip to the end result and see the same slideshow displayed from each site all on the same page.
Technorati Tags: PowerPoint, Zoho, SlideShare, Scribd, SlideAware, Splashcast,