"It is most likely that the sensor that tells the computer that your foot is on the brake is bad. To check for this, turn your key just out of the "lock" position, but do not turn the car on and see if it will shift from park (if you turn the car on, it will power the sensor and prevent it from shifting). To be able to drive it, just put it in neutral to start the engine, and select drive or reverse from there. Keep in mind that everytime you put it in park, you will have to use this procedure to get it out of park. Some cars have a small square that you pry off with a pocket screwdriver (located on the shifter) and inside is a little button that you can press with the pocket screwdriver and this will unlock the shifter. Hold down on the little button while shifting to the desired gear."
Found that with a 5 second google search. Hence the reason it's in quotations.