In this paper, we take the viewpoint that a teaching-learning process can be treated as a special type of workflow. Based on this and viewpoint, we propose a distributed architecture, which is based on BPEL Web Services, to realize a system compliant with the IMS Learning Design (LD), an international e-learning standard that supports multiple-role collaborative learning. In this system, a course described in IMS LD will be translated into a number of BPEL processes, which communicate with each other by invoking Web Services. The adoption of BPEL and Web Services contributes to the LD system in terms of flexibility, extensibility, and better integration with other e-Learning subsystems.