Roll Your Own Amazon S3!
Cross-posted from VirtZine – A company called Skylabel has released an open-source version of the Amazon S3 service which can be installed in a data center and be used just like Amazon S3 with the same tools such as Dragondisk, etc. Both source code and binary packages are available for download.
They have a quick start guide which will get you started very quickly, they claim you can be up in minutes!