You can use Mac OS X’s iCal to automatically run an AppleScript on a particular date and time. You can use this ability to send e-mails, interact with applications, and perform tasks without needing anybody around to oversee the work.
iCal is included with Mac OS X
Let’s ask iCal to run an AppleScript on 10 March 2011 at 10:00 am.
- Open iCal: Applications > iCal
- Navigate to the month of March.
- Click on the 10th March to select the day.

Open iCal and navigate to March.
- Create a new event on the selected day: File > New Event

Create a new iCal event.
- A New Event panel will appear; in this panel:
- Change the from and to dates to 10:00 am.

Change the new event's from and to times.
- Click on the None next to the alarm label.

Click on None, next to the alarm label.
- Select Run Script from the alarm menu.
- An open dialog will appear; select the AppleScript to run.

Choose the AppleScript to run.
- Once an AppleScript is selected, two new items will appear next to the alarm label: (name of the AppleScript) and 15 minutes before.

Two new items will appear after selecting an AppleScript.
- Click on the 15 minutes before, a little below the alarm label.

Select on date from the newly appeared menu.
- Select on date from the menu.
- A new date and time control will now appear. Change this date and time control to 10:00 am.

Set the date and time to run the AppleScript.
- Click Done to finish editing the event.
- Your new event is now scheduled.
There are a couple of notable limitations to using iCal as a scheduling tool:
- You must be logged in for the AppleScript to run.
- Your Mac must be powered on and awake when the event is due.