So, I just got my ZCS Open Source (test) server running, and I must say that it truly rocks. I've Administered everything from big sendmail/postfix (squirrelmail) systems to multi site Exchange clusters. Zimbra beats them all hands down.
Now, one of the requrements that I was given for this deployment/migration is that our users want a full OTA sync solution for their phones. We have everything from Backberries, to Treo's and WM5 devices (including my own personal Sprint PPC6700 which will be used for testing). None of which are currently being utilized to hit the Exchange server, because we all know how (un)safe it is to stick an Exchange server out on the public internet if it is not behind an ISS/OWA box.
I think the most elegant solution would be to use Funambol's sslIMAP connector to hit the Zimbra box, then push the new email down to the mobile units. Most of the ports on the Zimbra box are firewalled, but I could put in a rule that allows the one Funambol machine to get to it. IMAP would be a bit nicer than POP, since the servers and handsets could sync "read/unread" status as well.
Does anyone see any especially horrible issues with doing it this way?