Everybody loves e-Bay, including the scammers! This scam evolved from the 419 scam, but because it involved lower dollar amounts and new technology had a much higher percentage of success for the scammer.
In this scam, the victim places an item for sale on the Internet (not necessarily on e-Bay, often on local classified websites). The winning bidder contacts them to arrange payment, but there is a catch. The buyer is overseas and shipping needs to be arranged.
Payment is sent in the form of a counterfeit check for thousands of dollars in excess of the purchase price. The buyer is asked to wire the excess money to the buyer's shipper who will arrange pickup of the item (they are often told that there is a little extra money for them to keep for their trouble to sweeten the deal). The money is wired before the check comes back, leaving the victim (or their bank) out the money.