Its the same scam they've been pulling on people selling items online (vehicles, boats, etc.).
They send out an email to you with promises you'll receive a cashier's cheque for much higher than the price of the item you're selling. Then they instruct you to deduct your money and send the balance back to them via Western Union.
Meanwhile, the cashier's cheque is fraudulent...but sometimes it takes a week or more for your bank to realize this. By that time, they've got your money via Western Union, and you're stuck with a bum cheque.
Check out
http://www.joewein.de/sw/fraud-car-buyer.htm and
http://fraudalerts.blogspot.com/2005...s_archive.html