If, like me, you've been using Google Calendar to sync events to your Mac and iPhone, you know the process is a little convoluted; subscribe to your calendars in iCal, then sync either with GSync or with iTunes. With the release of iCloud, I decided to moved my calendar syncing away from Google for the ease of use. I have detailed the process below in case anyone else is looking to do the same thing.
If you haven't already, setup iCloud now in preferences. First thing you need to do is to create the same calendars in iCal that you have in Google Calendar (from herein referred to as GCal). To do this, open iCal and select file, new calendar then iCloud. Repeat this process for all the calendars you have in GCal. For me this was three calendars: Home, work and uni. Once this is done you need to log into the GCal web app. On the lefthand side, select the drop menu from the arrow of your first calendar. Then scroll to the calendar address section and right click on the ICAL button and select save link as. Name this whatever you want. Now open iCal again and select file then import. Select your .ics file and then choose which calendar you wish to import it into.
Repeat this process for each of your calendars, and you are now fully transferred from GCal to iCloud.