He's picking up
John Kerry, George Miller, and Tim Johnson as supporters. Johnson is, to me, the most interesting one of the batch. Obama partisans like to argue that he'll be better for downballot Democrats in tough races. That's a hard thing to prove one way or the other, but Johnson's one of the affected parties in this dispute so his judgment counts for something.
UPDATE: See also this post reflecting on
Obama's endorsements from the likes of Ted Kennedy.
This article available online at:
http://www.theatlantic.com/politics/archive/2008/01/obama-endorsements/47854/