Today, Google announced better CalDAV support which is excellent, but there is a huge issue with Google Apps for Domains. The CalDAV support only works for calendars for which you are the owner; Google Apps for Domains only has the owner specified for the Default domain. Any additional calendars you create don’t have the owner set so you can’t use them. I’m not sure what the issue is, but I’ve spent a few hours trying to figure this out and have gotten no where. Well, at least I can use CalDAV for one calendar (I tried this with my Gmail account and it works fine).