Here is a site I will be trying out soon. Combine a powerpoint and podcast to create a slidecast. Already at Slideshare.com is the ability to upload your slides to a server and have them run on your webpage. Now they add the ability to add voice to it by combining your MP3 file and you can set the page breaks so the slides are sync'ed with the audio. Here is an example of a slideshow embeded on a webpage (reviewing the DEE Conference).
If the slides do not show below try this link