The AP is reporting that the Department of Justice has closed its investigation into the U.S. attorney firings and will not file any charges.
The Bush Administration spent several years fighting allegations that it had fired several U.S. attorneys for politically motivated reasons, and then ignoring subpoenas by Congress to testify about the firings. Attorney General Alberto Gonzales resigned because of the scandal.
You can find past TPMmuckraker coverage of the scandal here and here, and a timeline here.