Had a helluva a time find any mention of this in American media, but it is in the Guardian UK (found via this Mississipifarian post). I first heard about this in the Sept 4 Democracy NOW! broadcast.
"Obama might pursue criminal charges against Bush administration"
· Biden says criminal violations will be pursued
· Democrats have issued subpoenas to Bush aides
· 3 staffers have been held in contempt of Congress
"If there has been a basis upon which you can pursue someone for a criminal violation, they will be pursued – not out of vengeance, not out of retribution, out of the need to preserve the notion that no one, no attorney general, no president -- no one is above the law."
However it might be a tease...
"What is true is the United States Congress is trying to preserve records on questions that relate to whether or not the law has been violated by anyone," Biden said, adding: "But, you know, there's been an awful lot of unsavoury stuff that's gone on. And the mere fact … that it occurred in a previous administration doesn't mean [a subsequent] Justice Department, if, in fact, there's evidence, shouldn't pursue them. "But I have no evidence of any of that. No one's talking about pursuing President Bush criminally."
Video of it here.