ADempiere is a business suite that has modules for ERP, CRM, MFG, SCM and POS. ADempiere was created on sourceforge as an open source project in September 2006. It's created actually on the platform of Compiere™ (developed by ComPiere Inc.), the crack being initiated by the different views between the developers of Compiere and the community that formed around that project (the community considered that the ComPiere Inc company was emphasizing too much the fact that the project is open source rather showing the community nature of the project. ADempiere in Italian means "to fulfill", but so does Compiere mean only that ADempiere is more like "accomplish"
vtiger CRM is an Open Source CRM software for small and medium businesses. vtiger CRM uses open source technologies such as Apache, MySQL, PHP (and other open source projects) to provide a powerful multi-platform CRM solution (works on Linux and Windows).
vtiger CRM provides the CRM features that other commercial programs sell for thousands of dollars, such as: sales force automation, customer support & service, marketing automation (with support for e-mail campaigns), inventory management (with product customization module), security management, and of course contact management and task scheduling.
Heap CRM is a customer relationship management application with modules like messaging, calendars and contacts. You can create reports on this data, or export the data, all in a web based interface that lets you administrate your customer relationships.
Siebel CRM On Demand is currently developed by Oracle, and as the name suggests it is an on-demand crm solution, meaning it will be accessed via the browser as a web service (web based crm solution). Siebel CRM On Demand allows you to perform sales management, customer service and management or to create/administrate your marketing campaigns. Latest version available is version 14, though Siebel CRM On Deman version 15 is right around the corner.
Infusion CRM is a web based CRM system developed by Infusion Software and targeting small and medium businesses. Infusion CRM offers features that help you automate an entire business process, starting with marketing and sales support, product billing, lead follow-up, and much more.
Unlike other hosted CRM solutions, Infusion CRM also offers and integrated shopping cart that allows you to track and process orders. This is an interesting addition given that you can track closely customers or possible customers and see what they purchased (and when they purchased), what marketing campaigns were they part of, analyze their behavior on your website and many other tracking options that will give you the advantage of knowing how to approach them.