OK replacing the slave cylinder is not bad. Its the getting to it part that sucks!
you'll be taking the tranny out (don't worry its not that bad) and moving it back or just taking it all the way out to get to the slave. O and what year is your jeep? 95 or so YJs have an external slave.
you'll take out both driveshafts - easy
take off the skidplate - easy, but make sure you've got something to hold the tranny, ie tranny jack, piece of wood, floor jack, a buddy, etc.
disconnect all wires,vents, hoses, going to the tranny& t-case - easy
Take of the shifter boot, and shifters from the tranny - easy, just make sure the tranny is in nuetral (dont' forget to block those tires) and just set it inside the jeep
take all bolts off the bellhousing holding the tranny to the engine. - this is the worst part, most of these bolts are different sizes, should be all metric/unless someone has replaced them at one time with standard. also getting up at the top of the tranny blows and is hard unless you have a body lift or some good ratchet extensions. You'll also need to have PB Blaster on hand to get the bolts to let go.
Ok once all these are off (and all your knuckles are blood and you've used up all your cuss words) just back the tranny and tcase off the engine.
Once your in there clean it up and swap parts
then reverse the install.
* I would go ahead and replace the clutch too while you are in there. Even though its probably still good, its better to replace it now then do this whole mess again when it goes out, i did.**