Perform the followings steps if you want to unlock ALL the worlds without playing through the game.
1) Load up Angry Birds and go to the ‘World Select’ screen.
2) Center a locked world on the screen.
3) Push the ‘Back’ button ALL the way out of Angry Birds.
4) Load Angry Birds back up and when the ‘Play’ button appears tap it rapidly.
5) You should be at the locked worlds ‘Stage’ select screen.
6) You must now pass the first level of each world to unlock it.