This paper describes a service-oriented approach for the integration of third-party external applications and resources into an existing open source eLearning environment. We detail the architecture for creating customized learning environments composed of existing open source applications and systems. As a result, a Web services-oriented framework for e-Learning systems is proposed, providing a flexible integration model in which all the learning components and applications are loosely connected. Web services provide a suitable deployment environment to realize dynamic and interoperable e-Learning systems by facilitating application-to-application interaction.