The Big Day Out 2007 is to be held on 19th January 2007 at Aucklands Mount Smart Stadium. Tickets go on sale October 19th. Theres also 5 dates in Austrailia after the Auckland gig, so no need to miss anything if you are over there right now.
Acts listed so far include:

Tool
Muse
The Killers
Jet
Minuit
Shapeshifter
Violent Femmes
Peaches
My Chemical Romance
Spank Rock
Eskimo Joe
Evermore
Scribe
The Veils
The Tutts
The Mint Chicks
Opensouls

Visit the official website for the full run down.