I've been following a thread on Fodor's forum regarding a fake listing on Homeaway (a site that I've used previously with no problems but am now a bit more wary).
The way that the OP has been treated by Homeaway is abominable and several posters have stated that they have posted the warning on this site however I have yet to find it.
It's a long thread however if you do not wish to read it all the relevant details are within the first few posts, in a nutshell a scammer has posted an advertisment for a luxury villa in Italy and has expressed payment direct (gave various reasons) the villa is actually located in Mallorca, rented out via a reputable specialist company so the OP booked and paid a substantial sum of money for somewhere that didn't exist.