Four years ago, in the course of a terrorism investigation, the FBI obtained the phone records of two Washington Post and two New York Times staffers working in Indonesia. FBI Director Robert Mueller recently apologized for this snooping, during which, as A.P. puts it, "agents did not follow proper procedures." From A.P.'s description, it sounds like the agents used "exigent circumstances" letters that demanded the records while falsely claiming grand jury subpoenas were in the works. A 2007 report (PDF) from by Justice Department's inspector general identified 700 such instances. Since the Electronic Communications Privacy Act (ECPA) generally requires a subpoena to obtain phone records, another way to put it is that the FBI broke the law, either deliberately or inadvertently. The bureau says "safeguards are now in place that we believe would prevent this from recurring." For one thing, the FBI no longer uses "exigent" letters, although it can always fall back on "national security letters," a kind of administrative subpoena that ECPA explicitly allows. The privacy of your phone records still depends on the executive branch's willingness and ability to police itself, of course. And given the government's new surveillance powers, so does the privacy of your email and phone calls.
[Thanks to Tricky Vic for the tip.]