If you're interested in working with graphics for Skyrim, you'll need some extra tools.
NifTools has several utilities for .nif (model) files, NifSkope and im/exporters for Max/Maya/Blender.
*Current version of NifSkope is 1.1.0 RC5, and this copy of nif.xml for NifSkope is newer, and offers better descriptions for the data you see, particularly in the shader config area.
Not all the tools are completely up to the task for Skyrim yet, current workarounds are in the tutorials listed here.
I think most folk are using Fallout Mod Manager to extract files from the .bsa archives.