Steering wheel doesn't lock anymore!

I'm having a problem with the steering wheel lock. Yesterday when I turned off the ignition, took out my key, and turned the steering wheel it wouldn't lock.:( Later on in the day it worked. This morning it started again and hasn't worked again. :confused:
Anyone else have this happen before? Any techs here who know how to fix it? If not I'll have to go back to the dealer. Thanks, Flower