Editions supported: Calendar resources are available in Google Apps for Business and Education. Compare editions now
If your Google Apps administrator has created Calendar resources (such as conference rooms, projectors, or other shared resources) for your organization, you can add resources to your events much the same way as you invite guests to the events.
To add a resource to an event:
Open your event.
On the right side of the event where you add guests, click the Rooms, etc. link.
Either browse the list of resources to find the one you want, or start typing the name of the resource in the Filter room text box until the desired resource appears in the list.
Click Add next to the desired resource. It will be added to the Where section in the Event details tab and to the participants list in the Find a time tab.
If you need to remove a resource you just added, find the resource in the list and click Remove.
To remove a resource that was previously scheduled for the event, you'll need to uncheck the Show only available box so you can see it in the resource list. Because the resource has already been scheduled, it's not considered available (except maybe if you also change the meeting time).