The use of ontologies to express the attributes of grid resources can provide a means to explore knowledge in this environment. Unfortunately, many grid initiatives have built their own ontologies, which are incompatible with the others. To achieve interoperability, ontology merge is a very interesting alternative. In this paper, we propose and evaluate a mechanism that performs ontology merging and semantic resource matching on the resulting global ontology. Also, we designed a graphical interface where the user can interact with our mechanism. As a preliminary result, we show that our tool is able to merge four different and complex ontologies that describe grid resources.