Terri,
I have a slideshow on my website (that I am working on improving...but that's another story). I created the PowerPoint as usual, and then used
www.authorstream.com to upload the slideshow and convert it into a video. Once you receive notification from authorstream that it has been uploaded successfully you can then upload it to YouTube. Once it is on YouTube, you can create an embedded link on your website to the YouTube video of your presentation. You'll need to set up accounts for both authorstream and YouTube. It's a long process and somewhat time-consuming but it works.
I'd love to hear from anyone who has figured out a better or easier way of doing it.