The simplest way to view meeting room calendars in Outlook Web App (OWA) is first to add the meeting rooms in the Outlook 2010 desktop client (see how to add a meeting room calendar in Outlook 2010 desktop client), then follow the instruction below to view meeting room calendars in Outlook Web App (OWA):
Sign in Outlook Web App (OWA) and switch to the Calendar view by clicking the calendar icon located in the lower left corner.
In the left navigation pane, click "Meeting rooms" or "Rooms" to expand it.
Check the meeting room that you want to view (in this example, I picked ACES 509), the meeting room calendar shows side by side with your default calendar.
If needed, close your default calendar so you'll see more details on the meeting room calendar.
If you have not opened or viewed a meeting room calendar in the Outlook desktop client, its calendar will NOT be listed in the Outlook Web App calendar under "Rooms". In this case, you need to open the calendar as another mailbox:
In the upper right corner, click the down arrow right beside your name and select "Open Other Mailbox" from the drop down list.
A box pops up and asks you to select a mailbox to be opened. You can click "Open..." to browser the global address book and select the meeting room from the list.
Or you can type "Library...", as soon as you start typing, a list of options will show for you to select, pick a room calendar that you want to view (in this example, I'll pick Room 314), then hit "Enter".
The meeting room calendar displays and you can tell from looking at the upper right corner.
Click the calendar icon in the lower left corner to view the meeting room calendar. You can switch it back to your own calendar by choosing to open another mailbox option again.