Sometimes, we have a problem to differentiate between governance and management, especially in IT aspect. However, there is a discussion about this in a group. I think this is one the best explanation to differentiate between governance and management.
IT Governance is a global challenge but. IT governance must be an integral part of corporate governance.
IT people and industry in general, make IT sound complex and scare people from corporate governance away. They just leave IT behind as they think its all too complex and things they wont understand.
IT governance should ensures that IT goals are met and IT risks are mitigated such that IT delivers value to sustain and grow the organization.
Now because IT management is mostly 'governing' itself. That is where the problems start. IT management always claim everything is fine and all projects are going great.
Because of lack (or at least the wrong usage) of performance matrices - there is little or no strategic alignment between IT investment and actual delivery.