There aren't any plain newbie tutorials for the material room unfortunately :(

 I was so frustrated with that room that I actually made a post asking for someone to walk me through it.  the bare basics of how to make nodes and connect them.  You might try the same thing.

However, there is really no way to learn highly detailed stuff in there other than to go in and make nodes and connect them in all kinds of ways and watch what happens and make tons of notes for yourself to reference for later.

I wish I could help but all I can really do in there is mimic what others do and then tweak settings. I can apply materials from the material library and also change colours of things, but that's about it.

Check at RDNA in the Node Cult forum. Look through the various threads for examples of material room setups. Some are really complicated and consist of many many layers of nodes. I can barely manage 1 layer, let alone 10 layers, LOL

Another thing to do is open some of your files in poser and look in the material room and see how things have been set up for that item.  Make some changes to the settings to see what happens, or add a node to make a reflection etc. 

Also, here is a post from bagginsbill when I was picking his brain one day about the material room and how he manages to be able to do such complex things in the material room.  Scroll down for further helpful posts from him too :)

http://www.renderosity.com/mod/forumpro/showthread.php?message_id=2778165&ebot_calc_page#message_2778165

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi