So for work I have to subscribe to a shared google calendar the company uses. Annoyingly this can't be through my Google Apps account though, it has to be through my normal google account.
Also annoying is the fact google doesn't let me subscribe to my shared calendars without making them 100% public. Which means the shared private calendar work uses would have to be a public shared calendar, which is obviously not going to happen. (Can't have everyone knowing when the secret drinking parties are!)
Thankfully, there is already a solution out there to this problem, and it comes in the form of a Preference Pane called SpanningSync that syncs iCal to Google Calendar. All you need to do is install the prefpane and enter your google email/password (which is then safely secured in your keychain I believe.)
What it does is stick an icon in the menubar, and then at a pre-defined (and customisable) interval, sync any new changes between the local iCal calendar and the remote shared calendar in your google acccount.
Spanning Sync is only $25 to register for the year, but you can save yourself $5 by entering 6EMQAC as the spanning sync coupon code, or clicking here