well it isn't hard if you know what your doing but yeah it is a very involved process. i'm not going to sit here and wright a novel to tell you how to do it but i'll give you a quick break down as much as i can. if possible the easiest way to do this would be to pull the engine.
first off you have to take the exhaust manifold off. all of the vacume hoses that are conected to the intake manifold, throttle body, and valve cover all have to be unhooked. all wire harnesses will have to be unplugged from the sensors, throttle body, and injectors. now the vavle cover and the intake manifold can come off.(note you can do some stuff without having to fully tear down every last part. ex:if you wanna leave the throttle body conected to the intake manifold and any hoses or wire that connect to the two you can leave them the way they are.)
next you would have to gain access to the timeing belt on the side of the engine. before doing this make sure that you mark the timeing gears with a grease pencil or something along with the crank position. this will help for when you put everything back together to set the timeing back to the proper location.(if this is not done right your motor will be trashed.) once the belt is off you should be to the point to remove the headstuds. the cams and valves should all be able to stay in the head so don't touch those. now that the headstuds are pulled you should be able to lift the head off and remove the old gasket. now put the new gasket on and add any sealant that is needed to make sure for a sealed tight fit.
now put everything back together and be extra sure that everything is tightened to factory torque specs. good luck but i highly recommend that you go to a pro mechanic for this.
I really dont even know when i was putting my header on there was oil just seeping out were the head gasket is i just now saw it. but its more than a little bit so i was going to change it because im always putting more oil in my car
Have you had any work done to the car? What are your driving habits? How many miles do you have on it? A head gasket leak is pretty unusual to have with this car, and any car actually, with low mileage (<150K).....unless not properly maintained with oil changes or if it ever overheated.