oooooooooh i know what you are talking about.... I have that happen everytime I start the car from a parking spot, go reverse, then turn the wheels to leave, *POP* ..... no idea what that is...thought it had to do with the steering column.
My car had the same issue, there is a service bulletin out for it. Mine sounded almost like a grinding noise, it only happened every few starts and lasted for a second or two. Some part for the starter, cant remember what it was called. Take it to the dealer, they should fix it for free.