From EZP Knowledge Base

Cron Jobs allow you to run scheduled tasks at pre-determined times. This is a handy tool to automate things as site updates, backups, etc.To create your own cron job in cPanel, simply do the following:

• First, login to cPanel!
• Then, click the "Cron Jobs" icon at the bottom of the page.

• Now select how often you'd like this cron job to run; The "Common Settings:" field allows you to easily schedule a task to be ran with commonly set time intervals. Or you can set your own interval by editing the "Minute:;Hour:;Day:;Month:;Weekday:;" fields.
• Next type the command that you wish to be executed on your set interval.

• You're done.

Note: You may also view and manage your currently set cron jobs at the bottom of this page

You can read more about cron here: http://en.wikipedia.org/wiki/Cronjob