I use a thing called muvee Auto Producer, as does Lara, the lady who makes the videos of the shelter buns. I have yet to buy the dumb thing, I just use up the "teaser" free trials. I have almost used up my last free trial, so I may have to decide to buy it or not soon. The good thing about it is that it is really really easy to use, you just throw in stills, video clips and an MP3 for your soundtrack, and it tries to match the tempo of the music to the action in the video. Quiet parts are overlayed with fades and stills. You have control over which portions of the video clips it uses, and you can change how the stills zoom and fade. On the downside, the thing is buggy buggy buggy buggy and there is zero customer support for it. You get used to saving your projects often, because it will crash eventually. There is also not much control over how the clips are layed out, so you cannot do a professional style video. You could download the free trial and give it a shot from the muvee website.
Another Haven volunteer uses the Microsoft movie maker tool to make neat videos out of text and pictures with effects (You an see an example on YouTube). This one is free from Microsoft. I have no idea how to use it unfortunately. I do know that this tool disapproves of Quicktime formatted files (.MOV), which is what my camera produces, so I cannot use it.
I also used a demo copy of the Adobe Premiere Elements tool. This is more like a professional video tool, where you have a time line and you put in cuts exactly where you want them. Lots of control, but very time consuming to use. The demo of this also puts an Adobe watermark on your video, so it was a non starter for me.