Here is another tool that you can use to publish your PowerPoint with audio. SplashCast does it all.
The SplashCast service enables anyone to create streaming media ‘channels’ that mix together video, music, photos, narration, text, as well as RSS feeds, PowerPoint presentations and PDF documents. These user-generated channels can be played and easily syndicated on any web site, blog, or social network page. When channel owners modify their channel, their content is automatically updated across all the web pages ‘tuned’ to that channel.
Thanks to Sarah for showing me this one.