Bacula 2 is an open-source-backup program that consists of several tools.

It is a little tricky to configure, but does just what you expect from a good backup program. There is a wide range of storage devices to hold the saved data (such as optical storages, hard disk, tape-streamer). It is based upon an server-client model and available on nearly every operating system (including Windows and Linux). The catalog is held in an SQL database. Bacula is scalable from a single stand alone computer to systems consisting of hundreds of computers located over a large network.