Follow this article to add an existing room as a calendar in Outlook 2010. This will allow users to create reservations and meetings on a shared calendar through an organization.
In Outlook 2010, switch to the Calendar view.
In the Ribbon, select Calendar Groups > Create New Calendar Group
Name the Calendar Group ‘Rooms’.
Search for ‘Rooms’, select the desired rooms and click ‘OK’.
You will now have access to the room’s calendar.