Popping in the front - Bushings?
 

2001 Jaguar XJ8 has some popping noise in the front. Bushings? anything else? What are the costs to repair?

I'm not a tech, but I wrote service for many years. If you are looking for any meaningful help here, you should be much more descriptive about when you hear the noise (while crossing speed bumps, turning into a driveway, just driving in general, etc.). It also helps to know if turning the steering wheel "causes/affects" the noise. Further, I would also mention Year, Make, Model, Mileage.
Typically, most popping noises require a close look at all of the front-end parts. Try rocking car at the corners and listen for the noise - also, I would certainly check for any loose bolts (like the air-spring/strut bolts), especially if any recent work has been performed. Furthermore, it can't hurt to make sure all of your wheels are properly tightened. A loose wheel can surely make a popping sound before it takes flight on the highway!! If it is none of those things, my next thought would be outer tie-rods (they are at the "end" of the hydraulic motion and, as such, they take more of a beating than some of the other front-end parts. Usually, if there is a problem, you will see a badly cracked/broken rubber boot on the tie-rod. Just remember that even though it is easy to replace a tie-rod - you must have a shop re-align front-end after. Hope this helps.