iCal 2 can combine multiple calendars, but everytime you update an event it adds another copy of the event to your published combined calendar. After weeks of arguing with their tech support, BuddySoft updated iCalPublish within a couple of days of my contacting them.
This programme simply works!
BuddySoft simply care about Mac users!
Download this now - and pay the shareware fee. This is what shareware is all about!