This article describes concepts, development, and implementation of an overall Open Access infrastructure for Germany. Currently, the joint project Open Access Network is facilitating comprehensive and value-added services built on top of distributed Institutional Repositories. Using the OAI-PMH as the harvesting mechanism, Open Access (OA) Network furnishes an open and extensible architecture to form the technological base for manifold enhanced services. It not only provides a personalized end user platform but also serves as an aggregator node for passing data to other service providers (e.g., DRIVER). Moreover, OA Network provides a testbed for the development of software to implement value-added services. OA Network is funded by the German Research Foundation (DFG).