Administrators in my school are constantly trying to balance calendars. In a school with around 2000 students and over 100 teachers, there is always something going on in the school community. How can you keep everything straight and make sure that major events don't overlap? I suggest google calendar.
Google's calendar is not only easy to use and edit, but it is also easily shared amongst your fellow administrators and staff. In as few as 3 clicks, you can share your calendar. Each administrator can have their own calendar and then there can be just a general school calendar that everyone can update. All calendars are separated by colors and are easily turned on or off depending on what information you need to see.
To add an event is as simple as a click. You can create a bubble that allows for basic information such as meeting at 3 or you can even add additional information such as how long the meeting will last and where it is located. Events can be shared too. If an administrator schedules a meeting that is to involve the other administrators in the school, he/she can share the event with the others and they will be notified of the added meeting.
The person that is in charge of the overall school calendar can also publish to the web so that the entire staff can access the information. This can all be shared via hyperlink and does not require a google login for your entire staff.
Google calendar can also be easily synched with Microsoft Outlook, ical and several phones.