Front end noise?

2002 Ranger, 62,000 miles. 32k miles when I bought it, and had an unusual noise in the (I think) front end. Sounds almost like a universal joint popping noise. Here's the really odd thing--it doesn't do it in cold weather. Only when it's warm. Seems to be coming from the steering, but really it's just hard to tell. Something you can almost feel as much as hear. Annoying, but doesn't seem to be getting any worse. Ideas? Thanks.