I’m so happy to see an official way to go back and forth between iCal and gCal (Google Calendar) for free!
http://lifehacker.com/5100841/calaboration-syncs-ical-and-google-calendar-with-ease
What is the big deal you ask? Well, using gCal to share a calendar is super easy and super useful. Having a central locale for people to see events helps so much at school. But updating it is easier for me through iCal. This is especially true if I’m updating from an email in Apple Mail where just one click it goes from email to iCal to gCal is very cool.
Plug-N-Play Education 