S3cmd
Command line tool for managing Amazon S3 and CloudFront services
...It is best suited for power users who are familiar with command-line programs. It is also ideal for batch scripts and automated backup to S3, triggered from cron, etc. S3cmd is written in Python. It's an open-source project available under GNU Public License v2 (GPLv2) and is free for both commercial and private use. You will only have to pay Amazon for using their storage. Lots of features and options have been added to S3cmd, since its very first release in 2008.... we recently counted more than 60 command-line options, including multipart uploads, encryption, incremental backup, s3 sync, ACL and Metadata management, S3 bucket size, bucket policies, and more!