I am a Systems / Email Administrator for a relatively small user base (300-400 users). We currently have a pretty basic setup for email. We have a Linux server running Postfix, and all the users have regular UNIX accounts on the server. All our clients use Outlook, but we are only doing POP3 email. We do not have any shared calendars, or group address lists. I have been pushing the company to move towards a more server-centric solution that will give us some of these "Exchange-like" features, but I definitely want it to be Linux-based software. I think Zimbra may be a good fit for our needs.

I'm planning on installing the Open Source Edition on a new server. Initially I would like to test just the email portion of Zimbra with one user. Ideally it would be user in our current email domain, and email would still come into our existing email server, but then forwarded over to the Zimbra server. The next stage would be to move a small group (5-10 users) over to the Zimbra server to test and/or demonstrate some of the other features, like the calendaring and group address lists. Finally, assuming I get a green light to proceed, I would probably want to move the users over in stages, although I would also consider doing it in one fell swoop.

I'm looking for ideas on the best way to proceed with this type of test and possible migration. Any thoughts or ideas would be greatly appreciated.