There is a huge potential for service providers to provide cloud based services. Specially SMB market will benefit from the services they can get from an SP. Saas like email or small database and Iaas for some special server applications. One other example is hosted voice solution.
Few early examples:
Orange Unveils Cloud Formation
Verizon debuts cloud computing service
BT and Cisco Deliver on Cloud Computing Vision with Launch of Pioneering Hosted Unified Communications Services