The iTunes Festival is a series of shows in London all September long. Beck's show was streamed live on iTunes, and archived for a short while. (Though when I watched the archive, two of the songs were missing.) The sound quality and video quality was pretty terrific though.
[people and bands
Banjo: Gus Seyffert
Bass: Justin Meldal-Johnsen
Cello: Gus Seyffert
Clavinet: Roger Joseph Manning Jr.
Cowbell: Roger Joseph Manning Jr.
Drums: Joey Waronker
Ebow: Smokey Hormel
Glockenspiel: Roger Joseph Manning Jr.
Guitar (Acoustic Slide): Gus Seyffert, Smokey Hormel
Guitar (Acoustic): Beck Hansen, Gus Seyffert, Jason Falkner, Smokey Hormel
Guitar (Electric): Beck Hansen, Gus Seyffert, Jason Falkner, Smokey Hormel
Harmonica: Beck Hansen, Smokey Hormel
keyboards: Jason Falkner, Roger Joseph Manning Jr., Smokey Hormel
Mandolin: Smokey Hormel
Maracas: Justin Meldal-Johnsen
Opening Act: Jenny Lewis
Piano: Roger Joseph Manning Jr.
Robot: Beck Hansen
Shaker: Beck Hansen
Synthesizer: Gus Seyffert, Justin Meldal-Johnsen
Tambourine: Gus Seyffert, Roger Joseph Manning Jr.
Vocals: Beck Hansen
Vocals (Background): Gus Seyffert, Jason Falkner, Justin Meldal-Johnsen, Roger Joseph Manning Jr., Smokey Hormel