Though PPT To Video Scout is a commercial software, you can get it absolutely free (no strings attached) as part of the "Giveaway of the Day" project.
To convert your PPT slides into video, you will need to have a copy of Microsoft Powerpoint installed on your machine since the software can only run from the "Convert To AVI" command in Powerpoint File menu. No stand-alone version.
But hurry up - you should download and install the software today itself (Feb 9, 2007) else the offer expires. Check the readme.txt for instructions.
Download PPT To Video Scout | GiveAway of the Day
Related: Create Flash Movies of Powerpoint Slides with Slideshare