This article discusses the new wave of folk music. It's got roots, a noncommercial attitude, but it also takes in influences of contemporary music, like punk and rock.

Update (evening):
And then there's this interview from Salon.com, with Amanda Petrusich, who wrote a book called It Still Moves, based on a road trip through the south for the roots of American music.

There's some reconsideration of American roots music going on, and some questions being raised about how to take the old and make it new.