This site isn't nearly spammy enough for the savages over at Digital Point but Flippa might be worth a try.

Also, if you're serious about selling, put a very visible graphic on every page with a link to a sales pitch PDF. The basic stuff everyone here has asked for should be included: traffic, revenue and background technology information.

With no revenue you're going to find yourself instantly offended by low-ball offers but you might find a diamond in the rough if you're patient.