GridPP Cloud UL
HEPiX Virtualisation Working Group
Tony's final report on this can be found here:
Ian Collier attended many of the meetings and Dave Kelsey in particular did a lot of work on the image trust and sharing model which was in turn the basis for teh EGI policy on VM image endorsement:
Andrew's Vacuum and vac page.
CernVM virtual machine etc project, including images and cvmfs
Wikipage tracking aspects of cloud security Security_Clouds