vtiger CRM is an open source Customer Relationship Management (CRM)
software mainly for small and medium businesses.  vtiger CRM is
built over proven, fast, and reliable LAMP/WAMP (Linux/Windows,
Apache, MySQL, and PHP) technologies and other open source projects.

Features: Sales force Automation, customer support & service,
marketing automation, inventory management, multiple database
support, security management, product customization, calendaring,
E-mail integration, add-ons, and others.

vtiger CRM provides as plugin: Customer Portal, Outlook Plug-in
for Microsoft Outlook users, Office Plug-in  for Microsoft Word
users, and Thunderbird Extension for Thunderbird mail users.

WWW: http://www.vtiger.com