There are many benefits for converting a PowerPoint presentation or slideshow to video: sharing on video-sharing sites (like Youtube, Yahoo Video, Metacafe, DailyMotion etc.) or taking along with hand-held devices (like iPhone, iPad, iPod, Blackberry, Zune, Creative Zen, PSP, Pocket PC, Nokia, cellphone etc.).
So it is absolutely necessary to know how to convert a PowerPoint file to video. The slideshow and the video slideshow will detailedly teach you 8 methods to convert PowerPoint to video:
PowerPoint: 8 Ways to Convert Power Point To Video