you can go on this
http://www.efestivals.co.uk/festivals/lineups.php
i dont know how accurate it is though
Reading Festival - Friday 22nd to Sunday 24th August 2008
Main Stage
Friday 22 August
Rage Against The Machine - to be confirmed
Saturday 23 August
The Killers - strong rumour
Bloc Party - strong rumour
Sunday 24 August
Metallica - strong rumour
Slipknot - strong rumour
unknown day
Babyshambles - strong rumour
My Chemical Romance - rumour
unknown stage
unknown day
Avenged Sevenfold - strong rumour
British Sea Power - to be confirmed
Broadway Calls - strong rumour
Cut Off Your Hands - rumour
Dizzee Rascal - strong rumour
Editors - to be confirmed
Foals - rumour
Frank Turner - strong rumour
Gallows - to be confirmed
Glasvegas - rumour
Less Than Jake - rumour
Los Campesinos! - rumour
NoFX - strong rumour
Plain White T's - strong rumour
Queens of the Stone Age - rumour
Story of the Year - strong rumour
The Automatic - strong rumour
The Cribs - to be confirmed