According to the Globe & Mail, Stephane Dion wants to bring down the Harper government in February.
The paper reports that Dion wants to take advantage of what he feels will be the fallout of the Mulroney/Schreiber affair and get to the polls before the Conservatives can bring in another budget.
I guess it's really a no-lose situation for Liberal supporters. It'll give Dion a chance to refute his critics and, if not, it'll clear the way for a new leader. I don't see any particular downside either way.