Be sure to read the manual that came with Poser 7.  I have Practical Poser 7 by Denise Tyler, although not sure if it is a great way to learn.  Best learning site is Dr Geep and there is also some video tuts at Geek at Play.  Honestly, one of the best ways to learn and grow is to constantly troll all the poser forums and read, read and read.  One book will not be able to contain all the scenarios you could run across or be as up to date.  I've been trying to learn DAZ Studio, Poser 7, Hexagon and C6Pro for about 2 years.  I still don't have enough time in the day to learn all I want! XD

Hope this was a bit helpful :) and Good luck!

~Crystal