Watch Prioritizing Your Product Backlog (75 minutes).
Pascal Van Cauwenberghe commented on the presentation:
Essentially, the process works on the theme level. Applying it to stories is too much work and is often meaningless to business users. When we work on a theme, we have to split them in stories and redo the exercise because not all stories in a high-scoring them have a lot of business value or are necessary to realize the theme’s business value. Overall an excellent presentation with good visuals, some exercises and practical advice.
If you'd like a hardcopy, Mike Cohn has released a PDF of his presentation.