If you're looking for a quick and dirty music video and have only still shots to work with, Animoto (http://www.animoto.com) is a good site. They synchronize your images with your music and combine them with video style transitions at the click of a button. It's not the same as a real video, but it's a lot better than your regular slide show and it's so painless to use compared to doing the real thing yourself that there's no reason not to have a look. You can make short clips to try it out for free, longer ones have an inexpensive subscription. If you don't like your version, you can send it back into the queue for a remix and it will generate a new one for you.
I asked about adding video clips (it doesn't *seem* that complicated - ha!), and they said that they have other features that would be higher priority right now. Too bad.