From Pitchfork:
Radiohead, Tom Petty and the Heartbreakers, and Jack Johson (headliners)
The fest has added Beck, Wilco, Broken Social Scene, Black Mountain, Devendra Banhart, Sharon Jones and the Dap-Kings, Bon Iver, Drive-By Truckers, Andrew Bird, M. Ward, Nellie McKay, Manu Chao, Regina Spektor, the Cool Kids, Two Gallants, the Coup, Steel Pulse, Lyrics Born, Cold War Kids, Café Tacuba, Little Brother and the Felice Brothers.
The Jack Johnson fan in your life will be sated by appearances from Ben Harper, Widespread Panic, Primus and Galactic, while the Tom Petty contingent will get a boost from Steve "Higher Love" Winwood.