If it's the coolant pipe across the front of the engine it's a fairly simple job, but access can be a nightmare. You'll probably find you can't move the heat shield without damaging it, not that this really matters.
Unbolt it, pull it out, get it out of the way. Put in the new one. There is a rubber gasket on one end that got stuck, but I was able to pry out with a long screwdriver. Refill with coolant.
Actually doing the job only took me about 10 minutes. Trying to get the old pipe out from behind the radiator, and get the new pipe in, took about 2 hours.