In today’s large collaborative environments, potentially composed of multiple distinct organisations, uniform controlled access to data has become a key requirement if these organisations are to work together as Virtual Organisations. We refer to such an integrated set of data resources as a virtual data warehouse. The Open Grid Services Architecture – Data Access and Integration (OGSA-DAI) project was established to produce a common middleware solution, aligned with the Global Grid Forum’s (GGF) OGSA vision [OGSA] to allow uniform access to data resources using a service based architecture. In this paper the service infrastructure provided by OGSA-DAI is presented providing a snapshot of its current state, in an evolutionary process, which is attempting to build infrastructure to allow easy integration and access to distributed data using grids or web services. More information about OGSA-DAI is available from the project web site: www.ogsadai.org.