iSpring free lets you convert a Powerpoint presentation into a Flash video which can be viewed online. Similar to what you can do with authorstream.com but since it's available on your PC (Windows only), you have more control. I can't test it because I don't have a PC, but it sounds like a good deal. I don't know if it retains any audio that has been added to the Powerpoint file. That would be a nice feature. The latest version, 5.7, is free for anyone to use with no licensing restrictions. It looks like iSpring does handle the audio in Powerpoint. Here's a nice explanation of how the software works .
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