One show already postponed after singer goes under the knife
Band played to 97,000 people in the California stadium
Triple-disc edition will be released on May 14
Bruce Springsteen, Madonna and Coldplay also raked it in last year, according to Billboard's Top 40 Money Makers list
The Edge says they've got "something really special"
Singer and rapper combine for new material
Bono, Christina Aguilera, Justin Timberlake set to feature in George Clooney-organised charity appeal
Actor is organising US telethon for earthquake survivors
The Edge says he's got over scepticism about festival's 'hippy roots'
Bruce Springsteen and Billy Joel also take in huge takings