In covering the debate over the stimulus bill, cable news shows booked twice as many Republican lawmakers as Democratic lawmakers, a survey by Think Progress found.
Before anyone blames the imbalance on a right-wing bias, first consider this is cable news, which has a bias toward ratings. Marc Ambinder of the Atlantic reasons that cable news bookers are looking to the White House, not Congress, to supply the Democratic response. While I'm sure there's some truth to that, I don't think it fully explains the disparity.
In the absence of reporting, the easiest way to appear like you're explaining something is to talk to the opposition. Not only do you get them to do the work of analyzing a complicated issue you don't really understand, but you look like you're holding someone accountable.
Of course, there's also an anti-bias bias at play - accuse the media of leaning left (and loving Obama) for long enough and they'll be sure to lean right just to prove you wrong.