Business case for moving services to the cloud

We've received this request from someone at a UK university and would be grateful if anyone could offer advice., share experiences, etc. If so please contact cloud@ja.net

'We would like to build a business case that includes comparative costs to be able to justify, or invalidate, the proposal that we should move some services to the cloud. Are you aware of anyone who may have developed such a business case for themselves or an organisation who could assist us in developing one?'