This paper introduces a novel approach for dynamic service establishment in a virtual organization. To allow dynamism semantic information has to be processed. A common language is needed. We introduce a novel approach called “Dynamic Service Evolution” (DSE) to establish bilateral agreements in an open process between services and clients. We have applied our approach in N2Grid and present a prototype in this paper. N2Grid is a neural network simulation system exploiting available computing resources in a Grid for neural network specific tasks. By the DSE we solve the problem, that no general standards (languages) for neural network representations exist.