Normally I use Windows but I got a Mac Mini and started playing with it. I set it up with MM Sync. I then published one of my calendars and all when well. However, unlike Google Calendar Sharing there does not appear to be a way to have security. It appears you can only publish as a "public" calendar where anyone can see it. Am I missing something? Also, it looks like it stores the calendar on MobileMe. So it appears that the Mac has to Sync ical with MobileMe Calendars and then Sync with the Published one. I hope Apple allows for Calendar Publishing directly from MobileMe.