With the incoming of new information technologies, including the WWW environment, more and more information resources as well as learning tools are available. The problem we address in this article is to provide content, easy access to heterogeneous resources (multimedia, multiple functions ...) and customized teaching aids. We propose the design of a global framework which enable the integration of various components with training worth, that can be selected through structured metadata. We focused more precisely on the description of teaching aids in the environmental domain and the experience we had with a simulation program in teaching courses.