I've used Windows Movie Maker, but then I'm a total newbie at this. It makes it easy to convert individual pictures (but not a PPT presentation, as far as I can tell) into a movie/video. When I'm better at it, I'll try Camtasia and Nero Photo-show. They sound great.
OOPS: EDIT: I just saw that the original question was three weeks old. Oh well. Maybe someone else would like to know.