Could u-Joints be going out?

We have a 2000 Chevy Suburban and this evening I had the window rolled down and I heard a 'squeaky' noise somewhere,sounded near the tires when I was driving very slowly. The noise was quicker as I sped up (of course) and I still heard it going a normal speed (60 mph). The vehicle drives smooth and I wouldn't have had a clue if I didn't have my window rolled down (can't hear it otherwise). I heard that it could possibly be a u-joint problem. Does this sound right? Should I have it checked out? Thanks