There's no doubt Twitter is changing journalism, but to my mind, only on certain types of story..and these are the mass event kind of stories when someone in the crowd of people involved and witnessing it starts tweeting.
And the cloud of tweeters range in on sources like @Nipp who was next to the tragic plane crash in Amsterdam this morning, and who finished the day with nearly nine hundred new followers and a line of interviews with news channels. As he said, surreal is the right term for this experience.
But twitter doesn't change all stories. I had a look for twitter coverage of the Financial Service Authority appearance in front of the Commons Treasury select committee this afternoon. It's pretty sparse, very partisan and tends to link to those 'old fashioned established news sources'. So for stories about one of the most interesting things to happen today it seems you still need a proper journalist.