1. Go to this eBay address and press the "add an eBay buyer to my blocked buyer list".

http://pages.ebay.com/services/buyandsell/biddermanagement.html

Remember to save this eBay address. By doing this you will prevent this clown from bidding on your future auctions.

2. To report a buyer who will not pay for an item won, go to this ebay site:

http://rebulk.ebay.com/ws/eBayISAPI.dll?CreateDispute&hc=1&hm=um.r%60can647

Remember to save this site as well. Through this means you will also be able to credited for your eBay final value fee.

Good Luck. I've over 3000 transactions, with more than 1500 sales. A number have been dead beats and their system is pretty good. If they haven't paid within 14 days, I suggest you offer it as a 2nd chance to the 2nd highest bidder, or just put it up for sale again. It would be preferable, from a legal standpoint, to go through the eBay attempt to get your money first. Then it's up to you as the buyer didn't live up to the contractual obligation.