Setting permissions on your MS Exchange calendar
Open Microsoft Outlook and connect to the mailbox that contains the folder that will be shared. In this example we will be sharing a calendar, but the process is the same for any folder.
Select the Folder List view, from the bottom left of your Outlook screen.
Right click the Calendar folder, select Share, and click Calendar Permissions.
From the Calendar Properties window you can add another user on your domain and give them permissions to view/edit your calendar. To add a user click the Add... button.
Select the users on your domain to set permissions for by locating them in the list and clicking Add ->.
The Permissions options are now available for the selected user. You can select a preset sharing option from the Permission Level drop down menu
You can further customise the Read/Write/Delete permissions for items on your calendar.
Click Apply, and then OK to set the permissions for the user. The second user can now log in to their mailbox and will be able to connect to your shared calendar.
Connecting to a shared calendar
Although the permissions for sharing have now been set, the calendar will not be visible to the second mailbox until it is added using Microsoft Outlook.
Open Microsoft Outlook and connect to the mailbox that will be sharing the calendar.
Click File, then click Open, and select Other User's Folder.
Click the Name button and select the mailbox containing the calendar you wish to share.
The shared calendar will be added to Outlook, and can be displayed by selecting it's tick box.
The available actions are determined by the permissions you set earlier when connected to the mailbox containing the shared calendar.