Developing outsourcing strategy

One of the goals that I have for 2008 is to reduce operational costs for the sales department. Although we run tight budgets, current economic conditions require a further reduction in costs to meet operating budgets. I am working towards formulating a strategy for outsourcing. I have read some cases studies where companies have leverage outside expertise and reduced their cost base. This is exactly what I am trying to achieve so I am hoping that the information I have will allow me to develop the correct approach.