I took mine off the MJ over the weekend to inspect. It's simply.
Jack up the rear, put the frame rail on a jackstand. Pull the wheel.
If your drum brakes are in good working order you should be able to pull the drum with little effort, mine slid right off, as soon as I realized that I needed to release the parking brake.
Make sure you chock the front wheels, and I put the Mj in 4WD and leave it in first. You don't want it rolliing off the jackstand while you've got the tire off.
If your drum brakes are worn to the point that you've got a ridge on the inside of the drum then you'll have to adjust the shooes to clear the ridge.
Mines a D35, so it may be different, but there should be some rubber plugs on the inside of the brake backer. Mine are on the bottom. You need to go to the parts store and get a brake adjuster tool, it looks like a bent screwdriver. You put the tool in and turn the star wheel inside the brake drum. I can't remember which way, but spin the drum after you turn the wheel. If it doesn't spin you've gone the wrong way. Keep cranking on the adjuster until you can get the drum off. It's a good thing to pay attention to how much you needed to undo it, as you'll have to adjust the brake shoes back to that position for the automatic adjuster to work properly. DO NOT pry on the drums with a screwdriver or prybar. You will more than likely damage the lip on the drum. I tried that once and learned my lesson. If you have to use force use a dead blow mallet and smack it a few times.
Honestly, if your drums have worn to have ridges on them I would look at getting them turned, or just replace them.
Here's a link that may be helpful:
http://www.partsource.ca/doityourself/JOM_May2005.asp
It may also be a good idea to pick up a haynes or chiltons manual. They aren't good for any major problems, but for a first timer the pictures are great.