Not yet, but we're getting close. The secret sauce so far is Google Apps for our family, Spanning Sync, SyncMyCal, Outlook 2003 at home and office, iCal, my wife's beloved but aging Samsung (PalmOS) i500, Missing Sync for Palm OS, and my battered and broken Palm Tungsten E|2. My demon-spawned Motorola RAZR is not invited, there's a seat waiting for the iPhone.
Here's the situation so far:
- Google Calendar on our family domain. The domain means I can easily share calendars internally without exposing them.
- In Google Calendar: a work and home calendar for me, a home calendar for my wife, child calendars to come. My calendar view includes my two calendars and my wifes.
- iCal is a natural fit to Google Calendar (gCal), so I create corresponding calendars on iCal for my wife and I on our shared home desktop. For example, my iCal desktop my personal, my work, my wife's personal, etc.
- Spanning Sync allows me to sync each of my iCal calenders to the corresponding gCal calendars, so we're in great shape on the Macs. gCal is the source of truth, but we can view the composite calendars on my MacBook as well.
- My personal Palm syncs to XP Outlook, so I need an Outlook to Palm solution. I'm testing SyncMyCal. So far, it's ok. Even handled some calendar name changes I threw at it. I need it because I want control over sync direction, only SyncMyCal offers that. Outlook is a weak match to gCal and SyncMyCal is not as sophisticated as Spanning Sync -- so I sync only my Personal calendar to gCal Personal and and to my Palm.
- The last step will be to instal SyncMyCal at work, so my work calendar will sync unidirectionally to gCal, bidirectionally to Exchange Server, and unidirectionally to another kludgy app I run on the Palm. [My work calendar uses every advanced feature of Outlook and Exchange server, I don't dare enable bidirectional sync to the much simpler gCal data model.]
Update 4/30/07: I ran into a roadblock on my journey to nerdvana  while testing SyncMyCal. The problem sounds a bit like this one, but I don't use ActiveSync. I do use Palm's Outlook sync conduits (HotSync Manager) and I also use a no-longer-supported .NET-requiring Outlook plug-in called Lookout for Outlook.
In my case I had two problems occur around the same time:
- HotSync Manager stopped responding. This happens every week or two anyway, so I don't give it enormous weight. I killed the stuck process in XP's process list and restarted it and it worked.
- After #1 the SyncMyCal toolbar vanished from Outlook and a restart didn't bring it back.
I'll update this post if/when I make substantial progress.
 Hardly surprising. When one creates a dependency chain of unreliable software components the probability that everything will work starts to get pretty low.
Update 5/7/07: SyncMyCal flopped for me. The install on my home machine was troubled, but I followed the vendor's FAQ directions and I was able to enable the plug-in. It worked at home for a week, so I tried it at work (Outlook Pro 2003 w/ Exchange environment). It crashed Outlook 2003 on startup. I tried a few times w/ rebooting etc, but it crashed every time.
I have sympathy for the vendor -- installing this type of functionality into Outlook 2003 is, I wager, a nightmare. I use 'Lookout for Outlook' at work and at home, and that's an unsupported plug-in now -- but I deeply depend on it. Outlook 2007 is incompatible with Lookout, so when we switch to 2007 I might try SyncMyCal again.
In the meantime, I'll try gSyncIt at home ...
Update 9/8/07: A blog dedicated to calendar interoperability ...
Update 9/6/09: I did eventually get this all sorted out! Actually, several times, since it changes every few months. There are some hints in this 2009 post. I have a unified work/home/family calendar now on both my iPhone and Google. I don't use OS X desktop iCal at all any more.