Its interesting to hear Apple supports CalDav, its not mentioned on their website (http://www.apple.com/macosx/features/ical/) or in the help files.

Kevin is the iSync beta available for the open...

I think the Outlook Connector and planned iSync adapter provide the tools neccessary for 80-95% of desktop deployments (assuming most users run Outlook or Mail/iCal). Thunderbird does a poor job of...

One of the nice features on OSX with Address Book and iCal is that if I enter a person's birthday into their contact details it appears in iCal in the Birthday calendar. This has saved me on many...

Subscribing works great but the Share dialog box needs to be extended in some way so to support sharing the .ics files with non-Zimbra users (or just to allow a non-technical user to setup the shared...

This is a pretty good NewsForge article on the subject of CalDAV:
http://software.newsforge.com/software/06/02/09/2140226.shtml?tid=74

In the article Cosmo seems the most relevant to Zimbra as...

I have setup the OS version of Zimbra and all seems to be running fine.
One thing that would be nice is if I could get the spell checker working outside my firewall without having to open port 7780....

I have only been pointed to Zimbra recently and I really like the browser interface and the tagging/searching capabilities.
What I am a bit confused about is the bundling of MySQL, OpenLDAP,...