I am selling another website via Flippa (formerly SitePoint marketplace). Although it costs $19 for a basic listing and much more to give it exposure, it is by far the best place to list a website or domain for sale and you get a much better response than listing a site on a forum.
I am selling my Twitter blog Time To Tweet. In my last sale I chose 2-3 weeks as the end date and used a buy it now. This time I decided to end the auction within 4 days, remove the buy it now and pay an extra $30 to display the blog for sale on the home page. Within a few hours it has already had 4 or 5 bids so I shouldn't have any problems selling it.
I am also selling Mixa.org, a great little 4 letter domain name which I picked up in an expiring domain auction last year. I'm sure it would prove to be a great domain name for a music related website. I have a dozen or so 3 or 4 letter domains so it will be interesting to see if Flippa attracts domain traders as well as website traders.