Just announced. Would be a better alternative for backups than S3 due to its price, although backup retrieval seems to take longer.
Amazon Glacier is a storage service optimized for infrequently used data, or "cold data."
Amazon Glacier is an extremely low-cost storage service that provides secure and durable storage for data archiving and backup. In order to keep costs low, Amazon Glacier is optimized for data that is infrequently accessed and for which retrieval times of several hours are suitable. With Amazon Glacier, customers can reliably store large or small amounts of data for as little as $0.01 per gigabyte per month, a significant savings compared to on-premises solutions.