I do it quite frequently, actually.
You initiate an order with the e-mail address you want the money sent to (Amazon Payments account). Once you initiate the order, it tells you the exact amount of coins to send to a Bitcoin address. Send the coins and within a couple of hours, they send you the money. Quick and easy.
I went today its not working it showning $0.0 amazon payment link says 404
I think its just hickup ?