This volume comprises the edited proceedings of the second CoreGRID Integration Workshop, CGIW'2006, held October 2006 in Krakow, Poland. A Network of Excellence funded by the European Commission's Sixth Framework Program, CoreGRID aims to strengthen and advance scientific and technological excellence in the area of Grid and Peer-to-Peer technologies by bringing together a critical mass of well-established researchers from 41 European research institutions. Designed for a professional audience of industry practitioners and researchers, the volume is also suitable for advanced-level students in computer science.