I recommend reading David Phinney's blog because I'm betting he's going to have some juicy stuff appearing in the near future as hearings on PMCs in Iraq kick off later this week.
If you're interested in the Christmas Eve shooting, I made a brief and quiet mention of it in my commentary on the UCMJ changes January 3rd:
It is folly to say the reason contractors haven't been prosecuted for things ranging from the so-called 'Aegis Trophy Video' to [a] possibly killing an Iraqi Presidential Guard in the International Zone on Christmas Eve is because Iraq is a "contingency operation."
Just a note on this, my sources gave me some good information before then, which I followed up on, including with a query to CENTCOM via phone and email. At first CENTCOM thought it was non-sense but when I provided some additional detail their public affairs liaison stopped responding to my email. This and others will be interesting test cases indeed.