There USED to be a company called The Repo Center Inc located in Miami - they closed in the summer of 2008. Some 'scammers' now have a website called therepocenter.net - using this old company's name, Better Business Bureau rating and corporate entries at Sunbiz.com.
Basically these scammers 'sell' you motorcycles or jetski's they really don't have. They sound very legit - and will ask you to Western Union three $900 payments to them as a deposit and which point they'll email you a bill of sale and deliver your product. They informed me that breaking up the wire transfers into $900 increments would save Western Union money transfer fees.
Once they receive your money - you'll never hear from them again.