Here is an excellent tutorial on how to place YouTube video into your PowerPoint Presentations. Personally, I use a lot of video in my presentations. However, I caution most people against this–There are numerous technical problems associated with video, even after you have figured out how to get it into your presentation.  Also, make sure you don’t use copyrighted material from YouTube in your presentation. YouTube has the billion dollar resources of the Google legal department to defend it; chances are that you don’t.