Found this blog about the scams. It wouldn't necessarily apply JUST to Craigslist; it could happen anywhere that checks or money orders are accepted as payments.
http://craigslistscammer.blogspot.co...es-to-buy.html
This isn't about home invasions/robberies, this particular scam is, as someone already mentioned, about the concept of a check written for a larger amount, and you're supposed to refund the buyer the difference. (I know someone who sold a piece of jewelry on eBay, and got taken in exactly this way.)