I'm happy to announce ClearCoin, my bitcoin escrow service:
https://clearcoin.appspot.com/
It makes bitcoin transactions safer by securely holding coins in escrow until both buyer and seller are satisfied.
If you are buying something using bitcoins, it makes the transaction much safer. If you are unsatisfied, you will eventually get your bitcoins refunded to you-- you can think of ClearCoin as do-it-yourself chargebacks.
If you are selling something using bitcoins, ClearCoin is safer than ad-hoc arrangements to reassure reluctant customers (like "I'll ship you the product if you promise to pay within 30 days" or "pay me half now and half on delivery").
I'm looking for questions, comments and feedback. You can give it a try for free-- transactions of less than 100 bitcoins are free, and you can setup an escrow account to yourself just to see how ClearCoin works.