Look on the Virgin festival site! Got mine already they are abour �150 for weekend camping tickets and usually about �80 for a day but worth every penny. They ususally go on sale around end of feb/march time.
Do you think there worth it, I don't, I went last year for the first time and couldn't believe the way people were treated by security, the prices and the complete and utter disgraceful state of the site.
Skip it and put all your eggs in the glasto basket, or be daring and try the glade or secret garden party. You wont regret it.