pwCatch, pwSurface 2, and pwEffect should install some READMEs and other technical documents in the “My Library” folder, but they’re the same documents that you’ll find on Posework’s web site, and they haven’t been updated in at least a couple of years (even though the actual shaders themselves HAVE been updated to work with DS 4.5). Actually, now that I think about it, the last date I saw on the Posework site was sometime in 2009—I’d almost considered it an abandoned site.
You won’t see any change in the preview window, or at best, the object you apply the shaders to may change to a solid white (or some other color)—the effect isn’t apparent until you render out the scene. Select the item in your scene that you want to apply the shader to, open the Surfaces tab, and when you apply the shader, you should see the extra channels appear.
As far as actual tutorials on how to use them, good luck—I looked a couple of months ago, and couldn’t find anything other than other people’s threads discussing how they had used them. Interesting reads, but not exactly comprehensive.