If you are happy doing the starter loosen trick, or have enough manliness to get the bolt off with a breaker bar then:
- Wait for car to be cool, then loosen top radiator hose from the radiator side. Coolant lose will be minimal as thats the highest point of the coolant system.
- Remove fan shroud (can loosly put top tad hose back in place for now)
- Remove fan belt
- Do starter trick/man strength with bar to loosen bolt
- Remove bolt, then use a small pulley puller to remove pulley
- Put new pulley on and reassemble
This method means you lose barely coolant and don't really need anything but tools and a new pulley to go on.
If you aren't happy using the starter trick, then drain the coolant system and remove radiator so you can try gunning the bolt off. You will also need to remove the radiator if your pulley removal tool is large and needs more space (i'd check this first once the fan shroud has been removed).
Think there are other ways of doing this job, but these are the ways i've done it to mine before.