The European Telecommunications Standards Institute (ETSI) delivered a 59-page report to the European Commission discussing the role of standards in cloud computing.
The report aims to serve as a detailed map of the necessary standards (inter alia for security, interoperability, data portability and reversibility) needed to build trust in cloud computing services.
http://www.etsi.org/images/files/Events/2013/2013_CSC_Delivery_WS/CSC-Final_report-013-CSC_Final_report_v1_0_PDF_format-.PDF
http://www.etsi.org