Are you wanting to market or sell the rights to this item..............there is a big difference.
And do you have a patent as of now.
Simply find a buyer. I know that sounds simple but patents have been sold on Ebay........this article will further explain the full selling of a patent. From beginning to end. If not satisfied then reject my answer or opt out on my answer and another expert will answer.
http://www.ehow.com/how_2039500_sell-patent-rights.html?ref=fuel&utm_source=yahoo&utm_medium=ssp&utm_campaign=yssp_art
Forensic Specialist
Over 20 years in the areas of Forensic Investigations.
This company is legit and does attempt to assist the seller in locating a prospective buyer of patents.
http://www.taeus.com/focusip.php?id=10