vtiger CRM is a Web-based customer relationship management (CRM) software. It was developed over SugarCRM (SPL 1.1.2), with sales force automation (SFA) features. It allows sales people to manage their valuable accounts, contacts, and opportunities effectively. It can also be used to track daily tasks, meetings, and email messages smoothly. Installation is hassle-free, and the intuitive user interface enhances the user experience.
http://crm.phpmagazine.net/upload/2006/06/vtiger5-thumb.png
The interface is really easy to use with drag and drop, advanced UI features, AJAX datagrids, in addition to many interesting tools such as the integrated RSS reader, Webmail, Calendar… etc. In the latest version, 5.0beta, a code cleanup was done, group calendar was added, a new user interface was devised for inventory modules, and automatic tax calculations are done. Migrating from version 4.2.3 to 5 beta is supported, and much more. vTiger is available for download under Mozilla Public License (MPL), commercial license are also available for commercial use.
More information and download at http://www.vtiger.com/