Heliophysics is the study of highly energetic events that originate on the Sun and propagate through the solar system. Such events can cause critical and possibly fatal disruption of the electromagnetic systems on spacecraft and on ground based structures such as electric power grids, so there is a clear need to understand the events in their totality as they propagate through space and time. The eScience challenge posed is that the data was gathered by many observatories and communities that have hitherto not needed to work together. Firstly, this involves the problem of helping users to more easily find and understand the relevance of data, especially data from outside their domain. Secondly, it involves solving challenges of data integration. We describe the design of the HELIO infrastructure, based on the use of Web Services linked together by work flows and accessible via portal-based user interfaces. We also discuss current progress in the implementation of this infrastructure and the feedback from the user community.