Zimbra is an open source messaging and collaboration software.  The Zimbra Collaboration Suite (ZCS) includes an email & calendar server along with an optional desktop application.  

Their web client integrates emails, contacts, shared calendars, VoIP, online document authoring and much more.  It’s no wonder they have over 60,000 organizations using their product.  Zimbra has also become one of the top email hosting choices for many Universities.

With their unique open source technology called Zimlets, users can directly access third party applications such as Skype, Salesforce.com and Yahoo! Maps.

ZCS deployment options include a hosted service utilizing Yahoo’s datacenters and onsite hosting where you would install the Zimbra Server software on your own hardware.

The Zimbra server is designed using other proven open source technologies, such as Apache Tomcat and MySQL.  Currently only Linux and Mac OS operating systems are supported.

On the front end, the Zimbra Web Client uses Ajax programming to bring a clean and powerful user interface.  ZCS also comes with a desktop application, but is also compatibility with other popular email applications like Microsoft Outlook, Apple desktop suite, and Mozilla Thunderbird.

Pricing for Zimbra products are:

• Open Source Edition: Free
• Standard Edition: 25 seat package, $25 /user /year ($625.00).
• Professional Edition: 25 seat package, $35 /user /year. ($875.00)

Prices are reduced as you purchases more than 50 users.  The Open Source edition does not come with any technical support, but you can still access the Zimbra Community should you have any questions or problems.