Easy:
http://offer.ebay.com/ws/eBayISAPI.dll?EndingMyAuction
If there are bids on the item just cancel all the bids, reason 'item no longer for sale'
To end your listing early:
1. Type your item number into the End My Listing Early form. (The item number is shown on your listing, confirmation email, and My eBay page.)
2. If there are bids on your item, select either ?Cancel bids and end listing early? or ?Sell item to high bidder.? If your item has no bids, you can skip this step.
3. Select the reason you're ending your listing early.
4. Your listing will end and will no longer be active on eBay. Bidders who did not win the listing receive an email that their bid was canceled and that the listing ended early.