Confirmed so far....
Alasdair Roberts - http://www.myspace.com/mewzach
An Horse - http://www.myspace.com/anhorse
Beirut - http://www.myspace.com/beruit
Billy Bragg - http://www.myspace.com/billybragg
Cass McCombs - http://www.myspace.com/cassmccombs
Field Music - http://www.myspace.com/fieldmusic
Fionn Regan - http://www.myspace.com/fionnregan
First Aid Kit - http://www.myspace.com/thisisfirstaidkit
Flaming Lips - http://www.myspace.com/flaminglips (Headlining)
Henry's Funeral Shoe - http://www.myspace.com/henrysfuneralshoe
Jack Northover - http://www.myspace.com/jacksebastiannorthover
Joanna Newsom - http://www.myspace.com/joannanewsomfansite (Headlining)
Matthew and the Atlas - http://www.myspace.com/matthewandtheatlas
Megafaun - http://www.myspace.com/megafaun
O.Children - http://www.myspace.com/ochildren
Pete Greenwood - http://www.myspace.com/petergreenwood
St Just Vigilantes - http://www.myspace.com/thestjustvigilantes
The Unthanks - http://www.myspace.com/rachelunthank
Voice Of The Seven Thunders - http://www.myspace.com/voiceofthesevenwoods
More Info: http://www.thegreenmanfestival.co.uk/