The Calendar feature allows you to share your calendar with other people, making it possible to greatly simplify the process of setting up meetings. You determine who has access to your calendar, and how much access they have.
Features in the Calendar Include:
Create reminders to have the calendar help you remember your appointments.
Create recurring events to schedule activities occurring more than once.
Create additional calendars
Compare multiple calendars and their schedules
Organize multiple calendars and choose which ones to display or hide
An Introduction to Outlook 2010 Calendar can be found here:
Outlook 2010 Calendar