We did this preliminary video on how our Beehive calendaring / contacts / task migration into Exchange / Office 365 works.
Look at it on full screen so you can catch all the details.
Updated July 18, 2013 to point to the final video.
Sumatra Development leads the field of migrating entire calendar servers to Exchange. We migrate Oracle Calendar Server, Oracle Beehive, Apple iCalendar, and Zimbra to Microsoft Exchange keeping all meeting information and resource bookings intact. We migrate calendars server-to-server between Exchange and Office 365 while keeping meetings live and doing incremental syncs quicker than any other solution.