Interest rates were cut again just again just a couple days ago. This 0% interest rate seems to be a desperate move. This means that if the economic situation gets any worse, there is little that Bernanke could do to help remedy the case.
This last ditch effort is aimed to be a jab at the banks and their prime lending rates. Right now the rates are around 4%, so lowering their rates even lower may indeed help stimulate a bit of the economy or at least stop more big companies from failing. But if this does not work, then things could be ad or worse for a long time.