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)
The usage pattern would follow:
1) Install the extension
2) Configure extension with your bitcoin address(es).
When encountering a site using bitwillet:
1) User clicks "Pay"
2) bitwillet overlay appears with generated bitcoin address to send payment to. bitcoin address is clickable.
3a) Clicking the bitwillet address interfaces with the bitcoin extension to send the payment from your account to the one provided by bitwillet. A "Are you sure?" confirmation should appear before the transaction is complete.
3b) Alternatively, the overlay interfaces directly with the extension and bypasses the need for the user to click the bitwillet address. Confirmation screen should still be used.
4) bitwillet overlay updates its text to tell the user the transaction is in process.
5) When the transaction is complete, the overlay message changes again to inform the user.