Large problems ranging from numerical simulation can now be solved through the Internet using grid middleware. This report describes the different steps involved to make available a service in the DIET grid middleware. The cosmological RAMSES application is taken as an example to detail the implementation. Furthermore, several results are given in order to show the benefits of using DIET, among which the transparent usage of numerous clusters and a low overhead (finding the right resource and submitting the computing task).Les problèmes à large échelle issus de la simulation numérique peuvent désormais être résolus sur des serveurs distants en utilisant des intergiciels de grille. Ce rapport décrit les différentes étapes nécessaires pour “g...