3 bolts hold the power steering gearbox in. you'll want a socket to get those bolts out (they are about 3/4 or 11/16 heads). there is a bolt holding the steering shaft to the box, you'll want a 10mm 12 point socket to get that bolt out, then the steering shaft slides up and off the box. you'll also need a couple line wrenches to get the fluid lines off the box. you'll also need a pitman arm puller (looks like something from the movie tron) to pull the pitman arm..
all in all it should take about an hour. it's a pretty easy job. you can rent the pitman arm puller from autozone or somewhere for free.. otherwise they are cheap anyway, like 15 bux.
i did sort of give the order of removal of things wrong.. do it in this order
1: pitmarn arm off
2: steering shaft off
3: cooling lines off
4: unbolt and remove box (3 bolts through frame)
edit: if you're replacing the steering box because steering feels loose, you should also check a few other things. such as, play in the steering shaft (a little plastic piece in the slip joint sometimes wears out, easy to fix) also check tie rod ends, ball joints, and axle pivot and R/A bushings while you're at it.
installation of the new box is opposite order