when i did mine, i was replacing the radiator too, so i pulled that first (after draining the system) (well, remove the shroud, then pulled the radiator). i left the fan on until i got the waterpump out. the waterpump bolts are different lengths iirc, so keep track of where they come from. to remove the studs for the fan, put two nuts on the stud tightened against each other and remove. when you install them on the new waterpump, make sure you install them tight (using the same method). if theyre not good and tight, they'll back of and the fan will wobble and throw the belt off (among other things). then where are you? stuck in a parking lot in the rain, with no tools, offering to trade beer to the quick lube guys if you can borrow a wrench (but maybe that was just me--different vehicle)
make sure the surface is clean on the block (and dry). i used orange RTV along with a new gasket. dont go too heavy on the RTV, you dont want it to squish into the inside when you tighten everything up. tighten it up evenly. i dont know the torque spec, i go by the german measurement system guudentite. thats pretty snug but not insane tight. i like to let RTV setup a little bit before i add fluid, but i think its probably superstition more than science.
if it were me, i'd go ahead and replace the tstat while you're in there too.
if you havent flushed your cooling system in a while, i'd do it prior to removing the old pump too. i like the hose-flush kits. run that, let everything cool, then do your pump and tstat.
when youre done fill'er up with 50/50% antifreeze water.