If there's any question that Twitter is changing the way journalism is done, here is a bit of evidence.
Take the speech being made right now by President Obama on the auto industry as an example. As Obama is speaking, some leading media figures are tweeting their reaction and analysis in real time.
Witness the Washington Post's Chris Cillizza. He grabbed a quote from Obama's speech, and relayed it to over 8,500 followers of his feed.
"We cannot and must not -- and will not -- let our auto industry just vanish" -- Obama
Cillizza also tweets White House press briefings @TheHyperFix several times a week. Air America's Ana Marie Cox is also known to live-tweet briefings.
In addition, a number of White House and congressional correspondents are active Twitter users, including anchors at major networks, and reporters for major newspapers. Many of the journalists tag their posts with the word "journotwits," to aid people in searching for their content.