Enable Google Calendar in Apple's iCal

Sync With Apple iCal or Mozilla Sunbird - Get Started with CalDAV

To set up CalDAV support for Google Calendar in Apple's iCal, follow these steps:

1. Open Apple iCal, go to Preferences and then the Accounts tab.
2. Click on the + button to add an account.
3. In the box that pops up, enter a description for the account and your Google Account username and password.
4. Under Server Options, add the following URL:
   
   https://www.google.com/calendar/dav/YOUREMAIL@DOMAIN.COM/user
   
   Replace 'YOUREMAIL@DOMAIN.COM' with the email address that you use to log in to Calendar. Make sure to include the '@domain.com' portion (which is @gmail.com for Gmail users) in this section.
   DO NOT substitute your username for 'user' at the end of the URL.
5. Leave the Use Kerberos v5 for authentication option unchecked.
6. Click Add.
7. Under the Delegation tab, select the calendars you'd like to add to iCal by checking the boxes next to them. You may need to hit refresh to get the latest list of calendars.
8. Add your email address to your Address Book card by selecting Add Email. You'll be prompted to add your email address only if your address is not already in your Address Book.

You won't be able to invite or email guests to Google Calendar events within iCal if your address is not in your Address Book.

Your Google Calendar will now appear in iCal's list of calendars, and changes you make to your Google Calendar in iCal will be reflected when you sign in to Google Calendar.

Event information will automatically refresh every five minutes. You can change this interval by opening the iCal > Preferences > Accounts menu and selecting a new refresh interval under the 'Refresh calendars' drop-down. Keep in mind you can also force a refresh by selecting a calendar and pressing the Apple and R keys at the same time.

Calendars that are checked but disabled have already been added to iCal - you can remove them from within iCal.