Note to Google and CSC, both companies I enjoy a working relationship with:
The Cloud is an accounting puzzle, not a technology one. Add up the costs of of hardware, software, bandwidth, secure routers, switches, the whole nine. Divide by the number of employees and there is the cost per employee. Divide this by 730 hours per month and that is the cost per hour per employee.
Security is an issue in any network that needs to connect to another network that connects to another network because you lose control of policy and enforment. The way to deploy a cloud solution is to add up the costs, divde by employees, then by hours. There are implementation costs and 'day 2' costs which are the caring and feeding.
The cloud is a collection of IT stuff (hardware, software, network, people) that we have been deploying for 30 years. Cloud is a billing application. Get the beancounters in to help with the clean up and the software jockeys to write an open source billing app and be done with it.