Traduzione in corso passo 4
Like the iPhone 3G and 3GS, there are two silver Phillips #000 screws at the bottom of the phone. Note: newer iPhone 4 handsets use 5-point "pentalobe" screws instead, requiring the use of a special screwdriver.
In a departure from the design of the 3G and 3GS, removing the screws releases the rear case, not the front glass.
This design makes switching out the rear panel trivial, but unfortunately means that replacing the iPhone 4 front panel will likely be rather challenging.