Are you looking for a robust email solution without licensing costs?

We recommend you try Zimbra.

Zimbra Collaboration Suite (ZCS) is an innovative way to manage communication for businesses. Zimbra helps integrate email, instant messaging, shared calendars, VoIP and online document authoring into a rich browser-based interface. Along with the listed key features, Zimbra is an open source messaging server and is the leading solution for enterprise, service providers, education, and government institutions. Zimbra offers administrators and their end-users a better way of being connected and staying connected.

ZCS includes an elegant Ajax based Admin Interface plus full scripting tools to manage their servers. Ajax based web collaboration is at the heart of this server.

Zimbra also fully supports standard-based API’s (IMAP / POP / iCal / CalDAV), as well as MAPI and iSync that seamlessly link with Microsoft Outlook, Apple desktop suite, and Mozilla Thunderbird.

ZCS can also inter-operate with an existing Microsoft Exchange setup and it's equipped with helpful migration tools to successfully migrate all exchange data into its system with ease.

The server also offers Zimbra Mobile for cell phones, which provides over-the-air "push" synchronization to smart-phones as well as a connector for BlackBerry Enterprise Server. The Zimbra solution comes with a high security package including built-in anti-spam and anti-virus scanning.

VENARC provides consulting and implementation services for Zimbra Collaboration Suite including High Availability clustering solutions.