Cloud Management in Enterprise Manager 12c is generating a huge amount of interest!! Have a look at the latest Cookbook by Oracle Product Management, this shows how to set up DbaaS (Database as a Service) step by step.
Database as a Service using Oracle Enterprise Manager 12c Cookbook
http://www.oracle.com/technetwork/oem/cloud-mgmt/em12c-dbaas-cookbook-1432364.pdf
Regards,
Porus.