Calendars → How to Use iCal
How to Import an iCalendar file
Copying an ICS file into Public Folder
Select the File Tab
Select Open & Export
Select Open Calendar
Navigate to find the ICS file you downloaded and click OK
A new calendar will be created in your personal mailbox called Untitled (1). It will be under your Calendar
Highlight the new calendar and then go to the View menu at the top of the Outlook screen. Look in the Current View section of the menu bar and select Change View.
Click on Change View and select List
Click on the calendar in list form and select CTRL +_A to select all then CTRL + C to copy the calendar
Go to the private folder or other calendar, repeat the steps as above to view the calendar in list form, then click on the top left cell, and select CTRL + V to paste the copied calendar. You can resort the calendar by date by clicking on the START column. When you are done, you can use the steps above to change the view back to Calendar view.
Importing iCal into a Google calendar
Importing iCal into an Apple calendar
Updated February 20, 2009