I read about the Zimbra Collaboration Email server in both Infoworld and Network world, so I went over to the website: www.zimbra.com
to check it out.
All I can say is wow. It is a really sweet collaboration software. They have a paid version and an open source version.
It requires FC3 or RHEL v4 update 2 running on a server with 2 Ghz processor with 2 ghz of ram, 10 gb of HD space for the program and additional space for message storage.
The only real downside is that the client computers need have 1+ Ghz processors with at least 512 MB of ram.
Which means that this software is geared for the enterprise market
Still it looks like a very useful product.