Francois of Domaining.com has teamed up with the Sedo.com domain marketplace to offer a great deal for domainers looking to promote their Sedo auctions. For only $50 (maybe a limited time offer, but I am not sure) you can feature your Sedo listing/auction on Domaining.com under the Featured Domains section in the left sidebar near the top of the page.
This would provide excellent additional exposure to an ongoing auction. From what I understand this only for running auctions and not just sales listings. Maybe Francois can chime in and clarify.