Alfresco is the leading open source alternative for enterprise content management (ECM). It couples the innovation of open source with the stability of a true enterprise-class platform. The open source model allows Alfresco to use open source technologies and contributions from the open source community to get higher quality software produced more quickly at much lower cost.
Alfresco is led by John Newton, founder of Documentum, and John Powell, former COO of Business Objects, and is backed by Accel Partners, Mayfield Fund and SAP Ventures.

Open-Xchange Server 5 delivers more than users expect. The rich interface provides a dynamic new experience. Secure and robust, OX delivers the power to share email, calendar, contacts, tasks and documents. In fact, OX includes 11 collaboration modules, more than any other groupware product.
You can access OX from almost any browser, rich client, or mobile device. It puts your mission-critical data at your fingertips. Through “OXtenders”, Open-Xchange connects to proprietary and open source rich clients and PDA’s. Users already accustomed to Microsoft Outlook need not make any changes in their …

Untangle has created one of the most impressive applications of this principle. The Untangle Gateway bundles together a list of applications that even seasoned sysadmins couldn’t install and effectively manage in a timely manner.
As the official name indicates, The Open Source Network Gateway, is open source. As with most commercial open source offerings, you must buy the Professional Package to get some features, but surprisingly few. All of the core functionality is included in the OSS version; enterprise management goodies augment the product for the Professional Package offering. – Charlie …

Spiceworks is a free “everything IT” tool that delivers nearly everything an IT pro needs to simplify your job. Designed for small- and medium-sized businesses, Spiceworks single, easy-to-use interface combines network inventory, monitoring, troubleshooting and reporting with an easy to use help desk. And, it connects you with a community of over half-a-million other IT pros to share ideas, best practices and product recommendations, and in the spirit of helping each other solve problems and make the IT day easier.