You may be interested in Duplicity, which can do encrypted backups to S3: http://duplicity.nongnu.org/ Duplicity uses the rsync algorithm for data transfer as well.
For those creating archives, you may be interested in xar: http://code.google.com/p/xar/ It preserves all the metadata such as SELinux information, ACLs, EAs, etc. On Mac OS X, it preserves all that, the resource fork and finder metadata as well. Two options are particularly relevant to backups:
--link-same makes identical file data into hardlinks, reducing space consumption both within the archive, and on disk when extracted.
--coalesce-heap when files with identical data are encountered, the data is only stored once in the archive, reducing the size of the archive.
For those creating archives, you may be interested in xar: http://code.google.com/p/xar/ It preserves all the metadata such as SELinux information, ACLs, EAs, etc. On Mac OS X, it preserves all that, the resource fork and finder metadata as well. Two options are particularly relevant to backups: --link-same makes identical file data into hardlinks, reducing space consumption both within the archive, and on disk when extracted. --coalesce-heap when files with identical data are encountered, the data is only stored once in the archive, reducing the size of the archive.