Spanning Sync is an Apple System Preference which will automatically keep your iCal and Google Calendars in sync. It works pretty well, in that "no fuss" way that you always want things like this to function. The downside is it's $25/yr after a 15-day trial, but it may well be worth it. I'd love to be able to use ALL the native collaboration and productivity tools on my personal machines, and keep everything working well together.
It does mean I'll have to convince work to ditch Oracle Calendar as a solution, though. It's definitely a "sunset" service, especially since it's been deemed by the application manager as "complete" and therefore we're stuck at a back-level version. If it weren't for that stupid thing, I'd now have ALL my various calendars synchronized.