In this detailed article Faisal Khan explains how to implement the Breadcrumb design pattern with Expression Blend and Silverlight 3.
Designing the patters for your user interface is crucial as far as the user experience is concerned. The need for implementing the Breadcrumb design pattern arises when you need to place an option for the users of the application to know where they really are; for example, in a hierarchical structure where users need to go forward and backward. It’s especially useful when you want to create navigational functionality which will allow users to move several steps forward and backward.