Provided you have the right tools, the whole process should only take about an hour.
I took a picture of the tool I used. It's called the "Power Bar" I needed this because I did not want to remove anything else from the car. Most repair shops would have one of these so if you have a friend there you might be able to borrow it. The way this works is, put a 27 mm socket on the end, onto the pulley bolt and a hammer. I have a picture to explain. The bolt is a "normal" thread that loosens anticlockwise and tightens clockwise. The bolt is very tight so it you use this method you might break a socket, but if you have good quality ones they should be up to the task. I'm not sure if the tool is an Australian thing but you can always use other methods to loosen the bolt. The safest method is to remove the starter motor and place a big flat screwdriver between the cogs, then you can loosen the bolt with a heavy duty (ratchet) wrench and 27mm socket. If you don't want to do this you need a fixed wrench (pictured) about 30cm long and with a piece of wood jam the end against the chassis of the car. Have someone turn the ignition key so the engine cranks the smallest amount possible. This will loosen the bolt but someone needs to hold the tool onto the bolt. Obviously if you have a viscous fan this needs to be removed before you can do anything. Once you've loosened the bolt the rest is easy. If you have not done so already, remove the drivebelt. After removing the pulley bolt the pulley should just "jimmy" off by hand and with a little patients (provided it's not rusted on). The pulley has a notch on it so it will only go on one way (no need to mark anything). Be careful not to damage the pulley end or the end of the crankshaft. Next comes the seal. The seal is in there tight. Use a screwdriver or some hooked tool to pries out the seal taking care not to damage the surroundings. Before you take out the seal note how far into the timing chain housing it was. Mine was flush with the edge of the housing. Lightly coat the new seal in clean motor oil and slowly press the seal into the housing. This is an important step so make sure you take your time. Try to push all sides of the seal at the same time so it doesn't bend. Take extreme care that you don't push the seal in too far because from the look of it, the seal can actually fall inside the housing. Now that the seal is back in, put the pulley back on. Now tighten the bolt using a fixed wrench (pictured) and hitting the end of it with a hammer. If you removed the starter motor to loosen the bolt it should be easy to tighten with the cogs still jammed up. If you used the hammer method you need to jack up the car and tighten the bolt from underneath where you can get leverage. With the car jacked up you will notice a small peep hole in the transmission (i think it has a plastic cover but mine doesn't). I inserted a socket between the casing and the bolt head to jam it up. Then you can tighten the bolt. Ok, now driverbelt goes back on and anything else you took off, and your done. This whole process should take and hour but I took 2 hours because I cleaned everything as I went. Cleaned the pulley, the front of the engine etc...Once you decide on a method to use to loosen the bolt the rest is easy (1 star out of 5 difficulty).
If you guys have any other questions, just ask.