Rdbackup is a small and easy to use backup system based on rsync and ssh. It works with a disk-to-disk backuping strategy where the data are stored on a single backup server. Rdbackup also provides a status monitoring through the SNMP interface.
plsync is a lightweight remote file synchronization software much like rsync, written entirely in Perl. It features a Perl module, a command line tool and a Network daemon. It is aiming at low ressource consumption (RAM, CPU) and maximum portability.
dProjects is a really simple centralized web and rsync based version control system for small groups. The clients can initiate the file movements from the web interface.