NIST publishes: Guidelines on Security andPrivacy in Public Cloud Computing

http://csrc.nist.gov/publications/drafts/800-144/Draft-SP-800-144_cloud-computing.pdf

It talked about the following topics for public cloud security and privacy:

Governance

Compliance 

Trust 

Architecture 

Identity and Access Management

Software Isolation

Data Protection

Availability 

Incident Response

 Summary of Recommendations