I’ve been trying to find a good way to sync my iCal with Google Calendar. Spanning Sync is a good solution, but it’s not free. Enter GCalDaemon. As long as you read the documentation and follow it step by step, it’s a breeze to configure.
I followed these directions: http://gcaldaemon.sourceforge.net/usage13-b.html
You can use a calendar you already have. The trick is finding it. By default, iCal stores it’s calendar files in:
/Users/*username*/Library/Application Support/iCal/Sources/
If you have more than one calendar, you’ll see folders with a bunch of random characters followed by .calendar. You can figure out which one is which by opening the Info.plist inside each folder with Property List Editor. Expand the Root key, and the Title string will have the name of your calendar.
Once you know which one you want to use, you can point GCalDaemon to it and you’re set.
Also make sure you check out the note about using Lingon to make the script run at startup. Very useful. :)