If you quit the Backup application, the backup will be cancelled. The software doesn't have to be open to perform scheduled backups; it will automatically launch at the designated time.

There is one major quirk with the Backup software that you'll want to look out for, especially if you've scheduled an automatic backup. The Backup application will continue to look for a designated destination even if it's not connected to your Mac. For example, I use a MacBook Pro as my desktop computer, and I've set a 1TB external desktop hard drive as a Backup destination. When I'm on the road, I don't have my 1TB hard drive connected; nevertheless, Backup will still launch and look for the external drive. I have to cancel that backup manually. This is a minor annoyance, but it would be nice if the software could stop looking for the drive after a certain amount of time.

Other backups with Backup

There are other plans you can use in Backup.

* Personal Data & Settings This specifically backs up data in Address Book, Stickies, iCal, Safari, and Keychain. The default destination is iDisk, but you can change this to a different destination.