Subscribe/Sync Google Calendars to iCal
Three to four months ago I moved a lot of my data over to Google's servers (bookmarks, mail, calendar, RSS reader). I knew that I was going to buy a new computer, probably a Mac. I also knew I didn't want to deal with migrating the data over to the new machine. Furthermore I figured that its best to be able to access your information from anywhere, rather than one computer. I'm fully impressed with all three web apps. But, now that I have this great portable computer, I may go some places that don't have internet access, and thus no calendar :(
OS X comes with a full fledged calendar app named iCal, and I figured that I'd give it a shot. If I had to move my calendar data, day by day into iCal I wouldn't even consider trying it. But, Google Calendar supports iCal quite well. Google Calendar basically offers the equivalent of an RSS feed of your calendars, and iCal supports subscribing. You can even subscribe to any public Google Calendars through iCal, which allows you to get Federal Holidays, Moon Phases, and many others. The process is pretty strait forward, but if you'd like a step by step walk through check out GoogleTutor.
Within 5 minutes I had imported all my Google Calendar data into iCal. I didn't expect it to go that smooth. There are limitations to this though. Any changes you make in Google Calendars will show up in iCal. However, changes made in iCal won't be displayed in Google Calendars. This is due to the fact that you are merely subscribing to a feed rather than syncing the two. After a bit of searching around I found SpanningSync. Although still in Beta SpanningSync will offer two way syncing between iCal and Google Calendars. Ultimately this is what you want. But for now, as long as you understand the limitations of subscribing you'll be able to get by till SpanningSync is officially released.