You can view other people's calendars in the Calendar view for OC Apps
Type the name of the person whose calendar you want to view in the search box in the bottom left under "Other calendars"
The default for a calendar that you haven't been given access to will just show free/busy time. There won't be details on the appointments, but you will be able to see when appointments have been made.
If you have been given permission to view a calendar, you will need to click on the link in the email letting you know you have received access. If you have only been given permission to view that person's calendar and make changes to the events, you will add the calendar like above.
If you have been given permission to make changes to the calendar and manage the sharing of that calendar, the calendar will appear under My Calendars. If the calendar doesn't appear right away after you have received the email that the person has shared your calendar, type the person's email address in under Other calendars (like above) to make the calendar appear. Even if you type the name under Other calendars, the calendar will appear under My Calendars.
(Click Here to view instructions on how to share your calendar with someone)