Book Recommendations on Cadence OrCAD
I've compiled a list of books, with brief descriptions of their coverage and intended readership, relating to spice simulation at

http://www.macspice.com/books

several of these may be useful to you. They include: 

Elementary SPICE


  
  The SPICE Book  By Andrei Vladimirescu.
  


Intermediate SPICE


  
  Inside Spice  By Ron M. Kielkowski.
  The Designer's Guide to SPICE and Spectre  By Ken Kundert.
  High Speed A/D Converters - Understanding Data Converters Through SPICE By Alfi Moscovici.
  SPICE Circuit Handbook By Steven M. Sandler.
  Circuit Simulation with SPICE OPUS By Tadej Tuma and Árpád Bürmen.
  


Advanced Spice


  
  Switch-Mode Power Supplies - Spice Simulations and Practical Designs By Christophe P. Basso.
  Switch-Mode Power Supply SPICE Cookbook By Christopher Basso.
  VLSI Circuit Simulation and Optimization By V. Litovski and M. Zwolinski.
  Semiconductor Modeling By Roy G. Leventhal, Lynne Green, et al.
  Node List Tolerance Analysis By Robert R. Boyd.
  MOSFET Modelling with SPICE By Daniel P. Foty.
  Transistor Level Modeling for Analog/RF IC Design By Wladyslaw Grabinski et al. 
  SPICE: Practical Device Modeling By Ron M. Kielkowski.
  Mosfet Models for Spice Simulation, Including BSIM3v3 and BSIM4 By William Liu.
  Semiconductor Device Modeling with SPICE By Giuseppe Massobrio and Paolo Antognetti.
  


Descriptive reviews for many of these books are available at the linked site, as well as a number of uncategorized/unreviewed books.