Yeah, Windows Movie Maker is by far the fastest method. You can burn it straight to DVD.
If your someone making an animation out of power point slides (a novice technique, but great if your bored on someone elses comp who only has Office....
) (You make tones of slides and on each on you change it a little bit, its fun), you shouldnt use a conversion tool to convert to video, but to swf. Plenty of free tools out there for that.
I see no point in getting a PPT/PPS converter (to video)