The Apache Open For Business Project is an enterprise automation software project that includes ERP, CRM, E-Business/E-Commerce, SCM, MRP, and CMMS/EAM functions. It is a foundation and starting point for enterprise solutions and can certainly be used out of the box, but is also great for creating specialized applications.
Dolibarr is a simple Web application with ERP and CRM capabilities. It is designed for small and medium companies, freelancers or foundations, and can be used to deal with all things you require to manage your activities, such as management of products, stocks, commercial proposals, invoices, orders, members of a foundation, and mailings. A single executable that installs the server and database is available for people with no technical knowledge.
PhpCompta is an accounting application. It is Web based and follows Belgian and French accountancy systems, but can be adapted to others. This application is able to handle the accounting for several small and medium-sized companies, and can create invoices or reports with OASIS or RTF templates. It can also manage analytic accountancy and follow-up of customers and suppliers. A plugin system is provided.