Compiere ERP+CRM is the leading open source ERP solution for Distribution, Retail, Manufacturing and Service industries. Compiere automates accounting, supply chain, inventory and sales orders. Compiere ERP is distributed under GPL V2 by Compiere, Inc.
OpenAspect - entire business, one place.
A scalable, secure ERP and CRM system, including Asset management/servicing, Inventory, Logistics, AP, AR, GL, and more.
Front-ends can be 'plugged-in', using PHP, ASP, Java, Delphi, and many more.