torn balljoint boot on '02?

I've never done any suspension work however I know a thing or two about cars (I've swapped my own cam, etc.). Anyways, noticed a torn lower balljoint boot on my wife's '02 Tahoe 4WD. How critical is it to get this fixed and how hard is it to do myself? I realize the ball joint grease is just oozing out and that dramatically decreases the life of the joint. Also, it looks like I would have to remove the joint to put a new boot on? If so could someone guide me along on this process, my Chilton's isn't much help. Truck has 47K if that matters.
Thanks