WordPress.org

1. Install and activate plugin
2. Add the widget to the chosen sidebar. Note many themes do not allow for this possibility, however you can add an additional sidebar to your header see WordPress SteppingIntoTemplates or Anmari`s widgetising headers
3. That`s it - customise the css and background image to taste.

Note: On the home page you will not see anything, you must drill down the navigation to see the breadcrumb.