Prince2 is a process driven and clearly defined project management method which became the de-facto-standard for the UK public sector.
It defines seven processes, each of them consists of a number of activities.
Processes are: Starting up a project, Initiating a project, Directing a project, Controlling a stage, Managing stage boundaries, Manage product delivery and Closing a project.
It looks to me very oriented to managing outsourced projects and, to do so, it describes a sound framework to interact to the supplier: control their progress, initiate and close the project.
Notes from http://en.wikipedia.org/wiki/PRINCE2