A friend(@wolever) and I spent the weekend hacking up a small web app which makes it easy for you to sell digital goods for Bitcoins. Once a customer has clicked the “buy” button, we take care of giving them a unique address, monitoring that address for transactions, then securely notifying your website once a minimum number of confirmations have been received. Oh, ya, and then we send you the Bitcoins :)The website is here: BitWillet: http://www.bitwillet.com and there is a demo on the front page.
(full disclosure: BitWillet uses the Willet, http://dev.getwillet.com, platform, of which I co-founded)