If Powerpoint can play embedded vod files, you could copy the files off the DVD and embed the correct file in a slideshow. Otherwise, you'll need to convert the DVD to a media format that Powerpoint understands (probably .avi, .mpeg or .wmv). That can be a hassle though, and you might need to spring for video editing software, which can get pricey (Sony Vegas and Adobe Premiere definitely have the ability to do this, but they cost in excess of $500.00).
I don't know of an "easy" way to do this, but I haven't used Powerpoint since I left school, so I'm rusty.