The shift from made-to-stock to made-to-order has resulted in new manufacturing environments that require IT frameworks able to support this new dynamism. Collaborative manufacturing environments demonstrate considerable potential in responding to this need. As such, open manufacturing approaches are becoming more and more the appropriate tool and technology to meet the high expectations of their customers, who, in today's economy, demand absolutely the best service, price, delivery time and product quality. In this paper an agent-supported infrastructure for e-manufacturing is proposed as the enabling tool for implementing virtual collaborative manufacturing environments. In such an environment an open manufacturing process is seeing as a virtual scenario in which different manufacturing services are choreographed and orchestrated in order to get a product by different autonomous entities from different manufacturing systems.