The default permissions on calendars allow others to see when you are busy but not details about the appointment. To allow others to see these details:

1. Right click on your calendar.
2. Click ‘Sharing Permissions’.
3. Click ‘My Organization’.
4. Click ‘Can view titles and location’
5. Remove other named users - those who have requested access to your calendar or those you have individually granted access. (Click the name then the ‘Remove’ button.) If ‘Anonymous’ is listed this can remain, as long as the permission is shown as ‘None’.
6. Click ‘OK’.

PRIVATE appointments will remain private!