This paper defines a layered multi-viewpoints structuring approach for the development of network-based distance learning (called telelearning) applications. The proposed approach covers the functional, architectural and technological views involved in such applications. We also identify three interaction levels: cooperation, coordination and communication and define generic functions related to each level for telelearning applications. We define MPLA, a Multi-Paradigm Layered Architecture that uses different technologies for implementation, integration and distribution of application's components. MPLA has been adopted to implement the CGTL (Co-operative Generic Tele-Learning) toolkit, usable for various synchronous collaborative groups.