This job takes a little bit of skill. Here's a synopsis:
You will have to remove the [upper] intake manifold to access the rear plugs. There are 6 gaskets beween the upper and lower IM's. The TB and EGR each have gaskets between them and the IM as well.
Start by removing the intake tube and the TB.
There are a couple of wiring harnesses and coolant hoses connected to the TB. When you're pulling off the lower coolant hose, be very careful. On my car, that hose leads to a plastic T-fitting which snaps very easily - it costs between $60 & $80 to replace.
After that, you can undo the 3 bolts for the EGR valve. Then pull the vacuum lines off. At this point, you're almost ready to remove the IM.
Before you wrestle the IM off (no exaggeration), you may have to unhook a few wiring harnesses.
There are 8 bolts that secure the upper intake manifold to the lower IM. Those bolts remain attatched to the intake manifold.
Once the IM is off, it's a walk in the park.
Do not to overtighten ANYTHING. I stripped one of the threads for the coil-on-plug. It barely took any force to do it, so beware.
Before you start, consider the following:
Seafoam treatment? I should have done one. This is what my lower intake looked like: http://i8.tinypic.com/25i4u4w.jpg http://i1.tinypic.com/25znocj.jpg
My upper IM was also very dirty. I used a can foaming engine degreaser to clean that out.
Carb cleaner in the TB. http://i5.tinypic.com/29gcwpi.jpg
Also, while you're back there, you could replace your PCV. Cheap insurance.
If you REALLY love your car, use electric component cleaner & di-electric grease on every wiring harness you can reach.