Fellow Mac users looking to sync iCal and Google Calendar - rejoice! For the Spanning Sync crew have re-opened their public beta to one and all. After their servers buckled under their first attempt at opening up the beta, they had to shut down temporarily. Fortunately, Spanning Sync's own vendor stepped up to the plate and offered some serious upgrades in infrastructure horsepower, and new users can officially begin signing up to use the beta once again.
If you head over and sign up, however, be sure to back up your calendars - after all, beta means beta. Doing something as simple as browsing to your ~/Library/Application Support/ folder and pressing Cmd + D on your /iCal/ folder to duplicate it will do just fine.
To grab your own copy of the beta, head over to their re-opening announcement post for the latest version. Simply log in with your Google Account (or go create a free one) to get swept off to a land of desktop + web service synchronization.