Google Apps has powerful calendar sharing and management capabilities. If you are trying to move a Google Calendar between one account and another, here are the steps required to make this possible:
1. Access the Google Calendar you are seeking to export.
This is a simple click on the respective calendar you want to export. You will then access the Calendar settings.
2. Select the iCal link to download
You can right-click or CTRL+click on this green button and save the file locally.
3. Access the new account and import
In the new account, simply login and select the Calendar Settings menu item in the upper right. From there, go to the second tab and select the Import Calendar link.
Select the respective calendar you would like to import into and choose the local .ics file you downloaded. From there, you will be able to see the new calendar. You can be sure to color code the separate calendar for easier event identification:
You now have your previous calendar in your new Google Apps Calendar and can manage this going forward!