<p>A little info on [http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html SuperDuper!] It is free, but some features are locked in the free version, like scheduled backups and other sorts of things.</p>
<p>Personally I do use this (bk) and I did pay for it, it is a great backup solution for over a network, however, it is very slow. Backups to a network volume are saved as Read/Write bootable sparce sparse images.</p>
<p>They have a wonderful feature though, its called Smart Update. Smart Update allows for the next time you backup, it only backs up the changed files from the last backup, which makes it alooot faster.</p>