How do you synchronize Google Calendar and iCal?
Solution 1:
Have a look at http://www.google.com/support/calendar/bin/answer.py?hl=en&answer=99358#ical. It lets you view and edit Google Calendars in iCal.
Solution 2:
I can recommend the free service of Nuevasync http://nuevasync.com from experience. It takes your Google Calendar(s) and syncs them to iPhone or others using a Microsoft Exchange protocol.
2 way syncing, multiple calendars, works like a charm, I've been using it non-stop for 10 months now I think.
When you set up syncing make sure to check the Default calendar in your iPhone Calendar settings to prevent any mishaps, you have to set this to your primary Google Calendar manually.