Cross Platform Groupware

[pardsbane at offthehill.org (Josh Pollak)]

Hi Guys,

Until we get a real sys-admin, I seem to be serving in that role at my 
new company. Currently, we have an xserver managing our user accounts, 
email, and mailing lists. I really like the xserve, but I'm starting to 
think we need some form of groupware system. The trick is, we need 
something cross platform. We have Linux, Mac, and Windows boxes here, 
and I am loath to impose any sort of order on the client machines until 
absolutely necessary.

The trouble is, I'm having a hard time finding good groupware 
solutions. Exchange is out of the question, because its MS, because its 
expensive, and because it sucks. I know there is Kolab, Citadel/UX, and 
the other projects supporting GroupDAV, but making sense of all this is 
getting tricky.

Ideally, this system would be supported by Mozilla, Firefox/Sunbird, 
KMail, Evolution, Outlook, Entourage, and Mail.app. At the very least, 
it needs to be supported by some client on each platform.

Does anyone have any experience with setting up a system in such a 
heterogeneous environment?

-Josh