I had to set up a new calendar on my iPhone and iPad, separate from the MobileMe account which has Mail, Contacts, Calendars together. Go to Settings -> Mail, Contacts, Calendars -> Add Account... -> Other -> AllCalDAV account.
Server: cal.me.com and the rest you know....
It seems to me that they are migrating to a new standard while phasing out the old one so although I had to turn off Calendars and add a separate CalDAV one, Apple are now directing people to this instead, which merges the old and the new (replaces old with new I reckon.) Hope this helps...
I still can't find how to sync my subscribed calendars with the new CalDAV account....
