Ara - That's true, just don't send him any type of deposit via Western Union, make sure it's something that you'd be able to get back if it is indeed a fraud, and better yet, avoid a down payment/deposit like that in this situation. Usually if someone's out to screw you, they say something like "We need a check via western union asap!" or something. When I tried selling my old car on autotrader, about 5 people emailed me saying they'd send western union, which is pretty much untracable, and by time they get the car (which has to be shipped to them, another sign of fraud), the check will bounce, and you'll be out of a car.
1998 Nissan Altima GXE