ball joints

[wade]

what is the best way to tell if your ball joints are shot? my truck was in storage for the past few years with a previous owner, as far as i can tell they have never been replaced, the top ones still have the rivots on them. the truck steers and tracks straight, but after you drive it for a few minutes the front end makes a terrible creeking noise. it happens when you turn the wheels and also when you push the truck up and down. all the steering componants seem ok. how difficult are they to change? any help in this matter would be greatly appreciated.