Backup

BackJack
A Macintosh based, fully automated, secure data backup and recovery service done via the Internet.
http://www.backjack.com/

Dobry Backuper
Mac backup software that creates full, versioned, and incremental backups. It creates tar-compatible backup archives and includes scheduling tools, on-the-fly compression, and backup to any locally mounted device, including CD/DVD and network volumes. [OS 10.3 or newer]
http://www.dobrysoft.com/

Mac Backups
Backup software enabling offsite storage of data. Download a free 30-day trial.
http://www.macbackups.com/

Qdea
Makers of Syncronize! and Syncronize! Pro. Both offer file syncronization and backup capabilities for multiple Macs. The Pro version also handles file server mirroring.
http://www.qdea.com/

Quik Sync
A file syncronization utility by Iomega Corporation that keeps a copy of your hard drive on Zip or Jaz disks.
http://www.iomega.com/software/

Retrospect
A backup program by Dantz Development for a single Macintosh or an entire network of Macs and Windows 9x/NT PCs.
http://www.dantz.com/

Shirt Pocket
Maker of SuperDuper!, a disk duplication utility for Mac OS X. SuperDuper! is designed to make it easy for users to isolate their computers from unwanted system changes. [OS 10.2.8 or newer]
http://www.shirt-pocket.com/

Tri-Backup
A backup program by Tri-Edre that can perform mirror or incremental backups as well as synchronization.
http://www.tri-edre.com/english/

MacZealots.com - Backing Up Your Mac
An overview of several Mac backup solutions. <small>(October 28, 2004)</small>
http://maczealots.com/articles/backup/