Step 1: Remove distributor cap. There are two screws, one is circled in red, one is on the other side of the cap. They take a phillips screwdriver or a 7/32" nut driver. If you remove the coil wire and one or two plug wires you'll be able to set the cap aside and leave the other wires connected.

You should now have something that looks like this:

That black thing in there with the wires plugged into it is the ignition module. Remove the three wire connectors. One is inside the cap and is shown with the yellow arrow. The other two are outside the distributor cap and can't be seen in this photo. Remove the two screws (circled in red) that hold down the ignition module. They are 7/32" hex heads.

It should now look something like this:

Clean up all the dirt and goo in there and make it look like this:

Now spread the new goo (it should be included with the new module) on to the mounting surface of the module and re-assemble. Piece of cake.

One final thing. Use a genuine GM module. Don't use a module that looks like this or you'll be doing the job over again soon.

The supplied grease is dielectric grease, good for insulating the heat sink on the bottom of the module from making electrical contact to the distributor. THe heat sink paste is a ceramic based compound specifically designed to isolate electricity, and promote heat disapation. It will keep your ignition module cooler, and make it last longer.

In simple terms, it helps cool the ignition module.

As for the effectiveness of the various compounds p8ntman442 mentioned, I'll let you know. I replaced the ignition module on my Formula a few months ago and I used the Radio Shack heat sink grease above (I've had that module sitting around as a spare and lost the grease that it came with). The car in the photos is a customer car that I worked on last week. This one got the grease that was supplied by GM with the module. If either one dies any time soon I'll let you all know.