This was a talk given at the second meeting of Brum Interaction Design Assocation. It discusses the method (but not so much the findings) of user-testing a GPS Trail application on a mobile device. Some videos and audio may not work, apologies.
Details also at: http://brumixda.wordpress.com/2009/09/04/outside-the-box-user-testing-context-aware-mobile-technology/
Clipping is a handy way to collect important slides you want to go back to later.