as i know a few folk are interested, latest additions are:
Sufjan Stevens, Shellac, Circulatory System, Grouper, Crystal Castles, Super Furry Animals, Boris, The Low Lows, Oneida presents The Ocropolis.

the oneida thing sounds amazing: "Oneida will transport the impetus, spirit and community of their multidisciplinary studio/performance space, The Ocropolis, to ATP for a full day of improvisation, collaboration, and recording, combined with the astounding Mighty Robot Visuals light crew."

full lineup:

Friday

The Jesus Lizard
Iron and Wine
Don’t Look Back: Dirty Three Performing ‘Ocean Songs’
Don’t Look Back: Suicide Performing First LP
Don’t Look Back: The Feelies Performing ‘Crazy Rhythms’
Don’t Look Back: The Drones Performing ‘Wait Long By The River’
Comedy Stage -Hosted and curated by David Cross

Saturday: curated by ATP

Animal Collective
Panda Bear
Sufjan Stevens
Deerhunter
Melvins
Shellac
Boss Hog
Autolux
Dead Meadow
EL-P
Anti-Pop Consortium
Circulatory System
Autolux
Atlas Sound
Akron Family
Grouper
Sleepy Sun
Bridezilla

Sunday: curated by The Flaming Lips

The Flaming Lips
Boredoms perform 9 drummer BOADRUM
No Age perform Husker Du
Caribou perform as Caribou Vibration Ensemble
Deerhoof with Martha Colburn
Crystal Castles
Super Furry Animals
Boris
Low Lows
Oneida Presents the Ocropolis

tickets at www.atpfestival.com