Great Scrum Retrospective
There' s a rather long but very interesting paper by Henrik Kniberg about his experiences establishing scrum with multiple teams over the last 12 months.
Lot's of really practical stuff in there including the things that didn't work so well. The information about testers and how they fit in the scrum process was excellent, and I see a lot of similarity in how he's structured his teams and been pragmatic in his approach and in what I've done.
If you're just getting started with Scrum or want some tips of fine tuning your problem areas go have a look!