Usually the reason for having to replace the upper control arm is bad bushings. Although it may be possible to find only the bushings (I couldn't) it would likely be more time consuming to replace the bushings instead of swapping arms. A new upper control arm will come with two new bushings already pressed) and a new ball joint.

Step 1: Jack up the vehicle and place it on jack stands. I only needed to replace one, so I only jacked up one side of the car. Feel free to do both.

Step 2: Remove the tire. This part isn't absolutely necessary but it makes life a little bit easier, and is easy to do.

Step 3: Located the upper control arm. It's easy to spot. It is shaped like an oversized horseshoe with a bushing on each tip and a ball joint in the center of the curve. Two bolts hold the bushing sides to the car and a castle nut holds the ball joint on.

Step 4: Begin to loosen the bushing bolts. I don't remember the exact size, but you'll almost certainly have to use a regular wrench as there's no clearance for a ratchet without removing the spring. If you have difficulty getting a bolt completely out because a coil gets in the way, simply place a jack under the steering knuckle and raise it up until the coil is JUST out of the way. Remove both bolts.

Step 5: Remove the cotter pin ad castle nut from the ball joint. The ball joint may simply pop loose, or it may refuse to budge. If it wont come off easily you have couple of options. Since you wont be reusing the ball joint you can work at prying it off with a large flathead screwdriver or a pry bar. Or, you can get a 2x4 and place it vertically: one end on the jack and the other end just under the control arm next to the ball joint. Pump the jack ONE TIME to put a little tension on the ball joint and then hit it with a rubber mallet.

Step 5: With the upper control arm removed, installation of the new upper control arm is the reverse. Align the bushings and ball joint, hand tighten the bushing bolts, hand tighten the ball joint castle nut, and then torque to spec. Don't forget to add the new cotter pin.

You won't need to get an alignment afterward since nothing major was touched. Some people decided to get an alignment afterward anyway, but I did not and have had absolutely no issues. Had you removed suspension parts to have more clearance, an alignment may be necessary.

Pictures will come later.