How+can+students+make+book+previews+on+U+tube+with+free+software?

There are a couple of tools you can use to make the video. On a PC there is a free piece of software called Movie Maker and on the the Mac there is iMovie (free). Both of these can import images. You can then add text, music or dialogue along with special effects. The video is then exported (shared) and uploaded to a youtube account.

If you have a PC there is software called Photo Story (free but may need to be installed) that is very good to use with images - but has some limits when dealing with text. Photo Story produces a movie which can be uploaded to youtube

(Another option is to use Power Point (PC) or Keynote (Mac) to put together images on slides then talk over them or add music then export the finished product to a movie file - or upload the presentation to a site like Slide Show or Google docs...)