Microsoft recently released a paper called The Economics of Cloud Computing for the EU Public Sector, which is actually valid for every other European country as well, as it is not too narrowly focused on the EU only. Additionally there is a US version of the paper. It is definitely worth reading.
Andrea Du Maio from Gartner offered his perspective on this paper in an article called Microsoft offers a refreshing perspective on government clouds – so it seems that the paper hit the mark. He said:
The paper is surprisingly refreshing since it does not try to match the reality of current Microsoft’s offering, which spans from on-premises, to dedicated and shared implementations, potentially able to meet any flavor of cloud. On the contrary Microsoft shows remarkable common sense in providing public sector clients with a realistic and cautionary picture about both private and community clouds
Roger