No surprise here. From The Washington Post:

Attorney General Michael B. Mukasey refused yesterday to refer two new House contempt citations to a federal grand jury, saying the White House aides involved in the case cannot be prosecuted because they were following legal advice from the Justice Department.

In a letter to House Speaker Nancy Pelosi (D-Calif.), Mukasey said the refusal by White House Chief of Staff Joshua B. Bolten and former presidential counsel Harriet E. Miers to comply with congressional subpoenas "did not constitute a crime."

So now it's on to court, where we'll have the novel situation of the House Judiciary Committee suing the White House.