ERP software can be extremely complex, as it must to meet the need and expectations of some of the largest and most sophisticated companies in the world. OpenERP is a modern enterprise management software based on Open Object, a modular, scalable and intuitive Rapid Application Development frame-work written in python. This review paper focuses OpenERP as Open source alternative to Enterprise level implementations for small to mid scale Enterprises (SMEs) and how open source ERP development can affect these enterprises. The paper will discuss core technologies and methodologies that are necessary for low cost ERP implementations in SMEs.