Outlook Team blogged about he Insert Calendar option that we have using Outlook.
During the summer season, I like to travel and visit my family and friends. Before I leave the office for my trips, I share these important dates with my colleagues so they know that I won't be around the office. Instead of sending an email message to my colleagues with a list of dates, I prefer to include a visual representation of my calendar.
On the Insert tab, in the Include group, click Calendar.
Read more at source: http://blogs.msdn.com/b/outlook/archive/2010/07/29/insert-and-send-a-calendar.aspx