Slide show video (seriously soon)

Hi. I need to put together about 40-50 slides made up of website print screens (step-by-step process of how a website works. Really just having one slide move in stop, and move out about 7 seconds later, and then same for the next ones... Obviously I'd like this to look nicely designed and professional, rather than just a plain white background and cheesy transition effect. I would also like to learn how its done and how to incorporate a nice tune in the background by doing all this next with you.