Poster JLHM has a idea that may work. Try this:
Here are the instructions modified for Snow Leopard:
Select iCal | Preferences. Go to the Accounts tab. Click Add beneath the Accounts list. In the ‘Account Type’ drop box, choose CalDAV, not ‘Automatic’ setup that will make it look like poop.
Enter your Google account and password. In the ‘Server address’ field input “https://www.google.com/calendar/dav/”, then open Google Calendar in your browser to get the Calendar ID of the desired calendar –> from the main Google Calendar page click Settings | Calendars tab | Click the desired calendar’s name and under Calendar Address (at the bottom), select and copy the long email address following ‘Calendar ID’ that ends in @group.calendar.google.com. Go back to your iCal Accounts Preferences and paste this long address at the end of the ../calendar/dav/ in the ‘Server address’ field, then append “/user/” at the very end.
The final string under Server address will look similar to “https://www.google.com/ calendar/ firstname.lastname@example.org/user”.
Click ‘Create’ and then close the Accounts Preferences window.