Over on my Official Blog, I take a look at the legal implications of the DOJ obtaining the phone records of the AP. (TL;DR: we don’t know enough yet; probably legal, icky.)
Looking to the bigger picture, it is difficult to get too bent out of shape about this happening to the AP. They, and most other news organizations, the erstwhile guardians of the freedom of the press, at best stood idly by, and at their worst actively encouraged, this sort of government intrusion during the darkest years of the Bush Presidency, gives this mess a soupçon of Schadenfreude.
That being said, no matter what the outcome of any investigations or whether there was a warrant properly issued or not, the chilling effect on the press and on leakers will be enormous. And that may just be the point.