http://www.livejournal.com/community/camera_sale/
As always, watch out for scammers. They generally aren't that spendy, so you might want ot insist on using reputable escrow agencies.
For you who are not familiar with escrow agencies, they are a thrird party in the sale of something. When the sale is made the seller sends the item to the agency and the buyer sends the check to the agency. The escrow agency then cashs the check. If the check clears the send the money to the seller and the product to the buyer, after keeping a percentage for themselves. As the agencies are bonded, you can't get out and out stolen from. It's still no defense against being shipped shoddy goods, so some caution is still needed.