I am an old school zimbra user -- played with it from inception to 3.1 when we implemented it.

I am working with a client now that uses a linux POP mail baised service, and pays $5/month/per account for that service.

They decided that they want to share the Outlook calendars that they have so that everyone in the office could see everyone elses calendars...

That brought them to me asking about Exchange Server. (which is too expensive for anyone let alone them!)

The currently have a total of 10 users, but 3 of these users are "Partners" and they each have a SmartPhone device.... All of which are different (of course)

One partner has a Treo 650, one has a Cingular WM5 device, and the other has a RIM blackberry phone.

Now if it werent for the phones, I'd say to them: forget outlook, go to zimbra, I can use IMAP to move their emails from thier current outlook profiles to a new zimbra server, and with Zimbra 4.5x they can share calendars and Contacts... there might be some bumps and they might have to manually enter their contacts into Zimbra, and they might have to manually enter their Calenders into Zimbra.... but thats the price they'd have to pay for using open source (read: not microsoft overpriced Exchange).

I can even sync the treo and Cingular WM5 devices email with Open Source Zimbra....
However the deal breaker is being able to sync the calendar, and being able to provide some level of connectivity to the Blackberry user.

So I am here to ask a few simple questions:
1. Using just the Open Source version is it at all possible to sync the calendar with any of these devices?
2. If I need Zimbra Mobile to do it, will it work with the open source version, and at what cost?
3. For the Blackberry -- I read through a bunch of stuff here on how to sync that, and the cheapest/easiest way seemed to be to sync a copy of outlook with the zimbra server, then sync the blackberry with outlook.
So I need the Zimbra Outlook Connector to do that right?
Can I get the Zimbra Outlook Connector to work with the Open Source version, if so at what cost?

Thanks in advance for your help --- I am basicly forced to combine all this questions into one thread. My "worst case senerio" will no doubt end up with links to threads answering all these questions from one central place, so it cant be a bad thing for me to ask this for others searching to migrate all these disperate devices into the sweet solution that is Zimbra.