iCal supports tentative approval of submitted events. This allows anyone with Add security access to submit a new event, but it will not be posted to the calendar until until someone with Edit security approves it.
On the General Settings Administration page, check Required Approval.
When checked, this will cause the Approve Events menu option to appear on the calendar navigation bar.
Edit Security must be assigned to the calendar. Those without edit access approval can tentatively add events for the calendar, but someone with edit access is required to post the event to the calendar. The security assignments are made on the security administration menu.
Approval of submitted events requires clicking on the Approve Events link found on the navigation bar located at the bottom of the calendar. You will be presented with a form that allows you to approve, delete or modify the events submitted for tentative approval. You might choose to modify the text of the event before submitting it to the calendar. There is month/day (Nov 12) beside each listed event. This link will guide you to the edit form for the event to allow full modification of the event.
The caretaker of a calendar configured for event approval can be notified whenever an event has been added to the calendar. The iCal system can be configured to send email messages to an individual (or multiple people) whenever an event is posted to the calendar. You can find information about this on the calendar administration menu.