If you’re used to calling cron jobs “cron jobs” then finding where to add one in Plesk 11 can be a bit hidden. In Plesk they are instead called “tasks”.
First login to Plesk and go to the “Websites and Domains” tab
Show advanced options
Select scheduled tasks
Choose the user that you want to run this cron (task) under
Select “Schedule New Task”
You can also go to the settings to customise email options