Currently Being ModeratedMay 20, 2012 5:02 PM (in response to amandad1102)
Check out this website. It's a great resource that actually has a tutorial video and article that explains exactly how to do this. http://imovietutorialhelp.com/imovie-slideshow-tutorial.html
It will answer this question for you for sure.
The iMovie Guy
may receive some form of compensation, financial or otherwise, from my video or link.