you need :
Make sure the transmission is in park (for cars with automatic transmissions).
Set the parking brake to prevent the car from rolling farther against the curb.
Pull hard on the steering wheel while turning it in both directions. If this doesn't free the wheel, move on to step 4.
Release the parking brake and put the transmission in neutral. Let up on the foot pedal just enough to rock the car slightly.
Turn the steering wheel again. The key should turn now.