It sounds like you are using iCal's ics subscription feature. Alas this is read-only and a long-remaining pain to admins.
The real sneak in the near term is to use the iSync connector to sync the calendar. I used these steps:
- User #1 creates a calendar in web client. I put some junk events to fill out the demo.
- Share to User #2 giving manager privs.
- User #2 needs to accept cal in web client. (Check the calendar to see that it is there.) This is a GOOD time to shorten/simplify the calendar's name! Shortening the name and removing punctuation will provide fewer headaches using and troubleshooting the share and sync.
- Fire up iSync in System Preferences in and check the box for the shared calendar. Run a 'Sync Now'.
- iCal should have refreshed to include the shared calendar.
- User 2 can add events and sync again. The calendar for both users #1 and #2 should eventually update. I verified this in the web client.
Anyway it seems to work for me. I am using 5.0.1 NE, with Leopard iCal and the iSync 5.0.1 connector. I would also love to test CalDAV, but that is NOT working for me. That is my next task!
Hope that helps,
Chris @ DPM