I have a '97 Camry and it started clicking after the car was turned off, on the driver side under the hood. Now, the key will not turn and the car can not be moved because the transmission can not be put into gear.
The only thing that will prevent a key from physically turning is if the lock cylinder is shot or the steering wheel is up against he safety steering lockout.
Try turning the steering wheel a bit in either direction and see what happens. Post back.