Environmental applications (support for territorial diagnostics, monitoring of practices, integrated management, etc.) have strengthened the case for efforts in the establishment of sharing and mutualisation infrastructures for georeferenced information. Within the framework of these initiatives, our work has led us to design and create a tool for cataloguing resources for environmental applications, MDweb. This tool can be used to catalogue different types of resources (digital maps, vector layers, geographical databases, documents, etc.) by using the metadata standard, and offers a search engine for these resources. The goal is to present this tool and make a focus on its originalities. After, giving the principles behind MDweb's design and its major features, we discuss about the interest to use associated thematic and spatial bases to give to the final users a powerful search engine and propose some components to assist and automatize the cataloguing. At the end, from a perspective of integrating MDweb as a component for locating resources within spatial data infrastructures, we intend to very shortly to implement the Catalog Web service specified by OGC, and also plan for the architecture necessary to integrate other such components that could be used in the framework of non-spatial data infrastructures. The semantic interoperability necessary to maintain consistency within catalogues and useful for conducting searches should be retained when the associated reference bases are shifted to a completely separate service.