Newsweek's Fineman:

I've recently spoken with two of the finalists for the role of Barack Obama's running-mate, and to two other sources who are close to the process.

My bottom line is this: Barring a big surprise or last-minute change of heart, the choice is likely to be Sen. Joe Biden of Delaware, chairman of the Foreign Relations Committee.

As a counterweight, this comes from a Democratic insider who has watched Biden for years and doesn't think it'll be him:

obama does not believe he needs foreign policy help, and does not want to create the perception that he needs the help....  he is very secure in his own skin with respect to what he knows, and the judgment and wisdom he brings, to national security decision making.  talk to hagel and reed and their traveling staff about the recent trip to learn about how confident and at ease obama is when it comes to the issues.  and, with respect to the most volatile aspect of the trip, the israelis may remain a tad nervous about the thin resume, but they are virtually unanimous in saying obama knows his stuff.  he clearly did not need biden on the trip to add credibility.  i have no doubt obama is looking forward to his debate with mccain on national security issues, especially since mccain will be set up as the expert and obama as the neophyte.  so, finally, when obama is in the white house, i bet he doesn't want joe biden, as much as he may like him, at his elbow thinking the VP is really in charge of foreign policy. 

--Michael Crowley