Easy Automated Snapshot-Style Backups with Rsync
http://www.mikerubel.org/computers/rsync_snapshots
"This document describes a method for generating automatic rotating "snapshot"-style backups on a Unix-based system, with specific examples drawn from the author's GNU/Linux experience"
rsync.net - Unix and Mac OSX Scheduled Backups
http://www.rsync.net/resources/howto/unix_backup.html
"Your rsync.net filesystem is accessible over either of the ftp or ssh protocols. This means that rsync, a common Unix tool that even comes standard in Mac OSX, is a perfect choice for periodic backups scheduled in cron."