Solved: How to sync multiple Google Calendars with an iPhone

Scenario: I have several Google Calendars in my life: a family hosted one, a personal one – attached to my original GMail account, and a work one. I want all my events to appear automagically, over the air, on my iPhone.

Prerequisite: You must pick one as the master calendar. I chose the personal calendar because that’s the GMail address by which folks know me (on email and GChat). I’m guessing you can undo all these steps if you decide another calendar ought to be the master, but save yourself the trouble and think a moment on how you want things set up.

Summary: After spelunking around the ‘net for a bit, I’ve come up with a set of steps that seems to work for me. What’s happening is that one shares the other calendars with a master calendar. Your scenario may be simpler, or more complex. I believe the following steps will work for your situation.

Caveats: I’m not sure that appointment invitations get back to the original calendars; it may be that they all go to the master calendar, but I’m testing that, and even in the worst case, at least absolutely everything is at my fingertips.

1. On your iPhone set up the master calendar to synchronize with your iPhone with the Microsoft Exchange functionality. As of iPhone OS 3.x only one Exchange sync may be set up. The official instructions, Mail, Calendar, & Contacts Setup: Setting Up Your iPhone or iPod Touch, do a good job of walking you through the steps.
2. On the desktop, for each of the other Google Calendars, log into the appropriate Google account and from the pull-down by the calendar name select “Share this Calendar”. You will be asked to provide the email address to which the calendar should be shared; I provided my personal.account@gmail.com information. You will also be asked to specify a level of information sharing. (Depending upon the administrator’s choices when configuring the account – I’m thinking mostly of hosted Google accounts – you may be allowed to only see the free/busy state, the information, and/or change the appointment information and even the calendar sharing configuration (although this tutorial doesn’t use the latter ability; I mention it only for completeness, even though I’m not sure it actually works.) Once you click Save you may be asked to confirm whether you really want to share information outside of the hosted domain; click ‘Yes’. An email will be sent to the master calendar GMail account, but it contains no links and you need do nothing; the calendar will be automatically added for you.
3. Log into the master calendar Google account and confirm that all the calendars you’ve shared have been received.
4. Still in the master calendar Google account visit https://www.google.com/calendar/iphoneselect and select each of the newly-shared calendars.
5. Back on the iPhone, visit http://m.google.com/ for the master calendar Google account and select the Google Sync icon. Select the device listed, and then the calendars.

The next time information is pushed to your iPhone – you select the interval on the iPhone in the Settings app under Mail, Contacts, Calendar > Fetch New Data – fire up the Calendar app on the iPhone and you should see the shared calendars. When an invitation is sent to any of the calendars it will appear on the iPhone. As mentioned above, I still have to play with this a bit to confirm that you can accept invitations on the iPhone, and where the reply is added (to the master calendar or the appropriate shared calendar).

If you fire up iCal on your desktop Macintosh you should see the shared calendars as well.

Plea: if you play with this before I have a chance to try it again, please email me where I’ve gone wrong. Many thanks.