The term 'cloud computing' is one of the most widely used in the IT industry today.  A range of significat developments are taking place that together will enable a step change in the ongoing evolution of IT service delivery.  This white paper reviews some of these developments, and with a view to the more practical concept of evolution rather than revolution, looks at how things can be worked into mainstream IT activities in an incremental manner.  It provides guidance on what 'cloud computing' translates to in terms of tangible and actionable specifics.