Since no resolution was posted, I'll dig up this kind of old thread and add to it a bit.
I have a similar problem, when I am backing out of my driveway (wheel turned hard to the right and one front wheel off the curb), about a third of the time, I hear a fairly loud metallic pop. It seems like I can avoid it by straightening the wheels before they reach the curb. Then when I go over the speed bump down the road from me, I can kind of feel it pop back in, although it is much more subtle.
Another possibly related symptom is when I am taking a somewhat hard turn over a bumpy road I can feel a very subtle jerk in the steering that makes the car feel less solid.
At least that is how my imagination is interpreting it. I've had all sorts of noises from my sway bar bushings and endlinks over the last couple years and have replaced my bushings and endlinks a number of times, but this noise seems substantially different.
I am really leaning towards my ball joints, but I cannot get them to budge with the car in the air with any force that I can apply. There is no slop in my steering or any noise when I wiggle the steering wheel back and forth which takes the blame off the rack or tie rods.
I actually put urethane bushings in my control arms last year about this time. My ball joints seemed fine then, but that doesn't mean they are still ok. The urethane bushings may also have put more stress on them and caused them to fail.
The popping started a couple months ago and hasn't really gotten worse. I have noticed my CV boots are leaking, not cracked just seeping out underneath the band clamps. The axles could probably be replaced, but I think if the noise was coming from any of the CV joints, it wouldn't roll too smoothly down the road. They are more known for making a clicking noise, not a pop.
My plan is to actually take my front sway bar off and see if the noise disappears. If it doesn't, I can at least rule them out. Then I guess it's cheapest things first.