Only by use of Grid technologies, the necessary ressources like computers, file systems, software tools, information systems and fast secure network connections can be combined in the required form to help researchers, developers, producers and users solving their individual tasks. In-Grid is based on six prototype applications in the fields of coupled multiscale problems, coupled multidisciplinary simulations and distributed simulation based optimization. Adaptive and scalable process models and runtime environments are to be developed. The aim is to give the user simulation-based tools on different levels of complexity.