We do cover most of this stuff in our tutorial section:

http://poser.smithmicro.com/tutorials.html

  The Nathan tutorial is actually pretty detailed:

http://poser.smithmicro.com/tutorials/Characters_model_import.html

http://poser.smithmicro.com/tutorials/Characters_grouping.html

http://poser.smithmicro.com/tutorials/Characters_rigging.html

http://poser.smithmicro.com/tutorials/Characters_morphing.html

The tutorial says it's for Poser Pro but Poser 8 does pretty much everything character setup-wise that Poser Pro did.