Commonly there are two steps:
1. Download a video from YouTube
It's very easy. There are many methods for you to choose from, You
will find a lot of methods to download video from YouTube.
here I recommend you use YouTube Downloader and Converter, not only
help you download videos from YouTube, buy also help you convert
YouTube videos to WMV, AVI, and MP4 etc which can be inserted into
PowerPoint.
Then the next step is embed the YouTube video to your PowerPoint.
2. . Embed YouTube video into PowerPoint
Tips:
Always put the movie in the same folder as your PowerPoint
presentation. If you later move the PowerPoint presentation to another
computer, copy the movie too. Keeping your movie in the same folder as
your presentation ensures the link will still work. However, you
should always test the movie on a new machine just to be certain. Re-
insert the movie, if necessary.
PowerPoint 2003 and PowerPoint 2007 may a little different.
Tutorial with Screenshots:
http://www.ppt-to-video.com/knowledges/embed-youtube-powerpoint.html#105
You can also upload your PowerPoint to YouTube for wide-sharing.
Tutorial with screen shots:
http://www.ppt-to-video.com/blog/how-to-view-powerpoint-on-youtube.html#105
Hope it can help
