Just a quickie tip here: If you have an iPhone, you may be experiencing problems in syncing events with your iCal calendars. I know I was! I have a regular iCal calendar and then a CalDAV account with a series of other calendars within it. Only the regular iCal calendars would show up for syncing in iTunes, and not always reliably. I discovered that my problems were solved when I removed spaces from the names of all the calendars (iCal or those from my CalDAV account). Now all the calendars show up in iTunes and can be sync'd to the iPhone.
I still can't write new events from the iPhone into a CalDAV calendar (as Apple hasn't made that possible yet), but at least I can see when and where I need to be tomorrow!