This is a quick writeup on how to change your power steering pressure line. My old line was weeping out of the rubber part, kind of like a garden soaker hose, and had saturated the foam insulation and begun to drip on the catalytic converter and make a nice James Bond style smoke screen behind the car. Sorry no photos, I was too dirty when I did it so I couldn't take pictures. I may take some "finished" pictures when I am under the car and cleaner.

Compatibility Warning:
This protocol is written for four-cylinder cars with the later body style. I don't know how the V6 or the early body style change things, so proceed at your own risk. Also, this protocol is written for left-hand drive cars. Right-hand drive cars, such as those found in Japan, the UK, India, and Ireland, may be entirely different. I bet the fittings are the same size, though.

Tools required:
-Open-end wrenches in 18 and 16mm
-Tubing wrenches in 18 and 16mm (optional, but nice)
-Torx T35 socket attachment (I think). You cannot use a screwdriver style torx driver. It will not fit. You need a bit that you can mount in a ratchet or short T-handle.
-Drain pan or something to catch about a quart (1L) of power steering fluid from under the car.

Parts required:

-New hose (or have a hydraulic shop make you a new hose)
-About 1.5L of power steering fluid (see below)

Difficulty: 2/5, only because it's under the car and you're doing a lot of work by feel.

It's not too bad a job, but requires either the patience of a saint or a lift.

1) Raise the car in the front on both sides. You can do this with either ramps or jackstands, but you will need the left front wheel off eventually.
2) Take off the left front wheel and look at the power steering lines, where they meet the rack.
3) If you have tubing wrenches, now is your time to use them. Fit the 18mm wrench to the line coming off of the rack. The pressure line is the lowest large-diameter line. Follow it back and forth with your eyes to make sure you're removing the right one. Then loosen the line. It should not require much force. The makers of the rack were smart enough to make the part that the lines thread into out of cast iron, so there is no corrosion to seize the fitting in place.
4) Once you have loosened that fitting, go find the pressure fitting on the bottom pump. I found it from under the car. You may also be able to see or feel it by taking the right wheel off. I did not have to remove the fender liner for this at all on either side. Use the 16mm tubing wrench to loosen this fitting.
5) Once both fittings are loose, you know you will be able to remove the line. Position your drain pan below where you're working (left side of car under rack). Take the fitting on the rack completely off and push the line out under the car, so it hangs into your drain pan. Let the fluid drain out of this side. While it is draining, use the Torx bit to remove the screw holding the clamp for the power steering hose to the engine while the hose.
6) Remove the fitting on the other side.
7) Remove the hose, out the left side of the car above the tie-rod boot.

At this point, you have some options. Either you've bought a new hose, or you could get a hydraulic shop to re-make your old hose by putting new rubber hose in between the metal pieces. The hydraulic shop will probably charge you about $40 or so, depending on where you live. If you are using your old hose, make sure you replace the O-rings! Some new hoses may not come with the factory protective foam. Since the hose sits above the catalytic converter and may get a lot of radiated heat, I advise home-making a protective shield for the hose out of a length of radiator hose.

8) Position the new hose by inserting it the same way you got the old hose out.
9) Screw the fittings back on. Make sure your new hose came with O-rings. If it didn't, I recommend going to your local auto parts store and seeing if they have anything to match the ones you removed. The fittings can be tricky to get started. I had to use a wrench to start both of mine, after trying in vain to put them on by hand. It is especially hard to do if you can't see the fittings.
10) Tighten the fittings. They do not need to be very tight at all! The factory torque is like 20 ft-lbs. Since you can't really use a torque wrench, I advise tightening them on the loose side, filling up, and then seeing if you have leaks. If you don't, then leave them. If you do, tighten them some more. If you go too tight, you will squash the O-rings and have to buy new ones.
11) Fill with power steering fluid. The official GM spec is 9985010. Pentosin also works. Don't use universal. They do not recommend this for a complete fill, only for topping off existing systems. You've essentially re-filled your entire power steering system, so use the right fluid.
12) Check for leaks, both near the pump and on the rack.
13) Use the Torx bit to re-attach the clamp that holds the hose to the engine on the back side.

Good luck! It wasn't so bad for me, and hopefully this makes it even easier for you.