MSP automatically backs up your database each time you shut down the program, and the last 25 of these backups are stored locally on your computer.
You can also do regular backups of your database by choosing "Backup Database..." from the File menu at the top of MSP's main screen. You can then save the backup copies on a CD, or other removable media that is not your primary hard drive on your computer. This ensures that you will be able to restore your Minister Scheduler Pro data even if your computer's hard drive fails.