Here is a link to a story from KSL-TV in Salt Lake City about a guy who used his home camera system to catch a pair of crooks who had stolen some equipment from his garage (click on the video screen on the top left corner of the screen once the page loads to watch the clip).
Although the reporter makes the suggestion at the end of the story that cameras are a deterrent (I don’t think that they are), this story does show how CCTV systems can be used as a tool in solving crimes after the fact.