OK here is a start of some links........
THE MARIJUANA GROWER'S GUIDE..........by Mel Frank & Ed Rosenthal
This is some of Ed Rosenthals book...good read
International Cannagraphic Magazine Forums - The Complete guide to Sick Plants,pH, and Pest troubles!
One of the better sick plant guides I've come across
Cannabis Nutrient and Deficiency Table
Marijuana Plant Problems and Cures
This one is definately in the wrong area...I was on this site for over a month before I used it.
http://www.ganjaguerrilla.net/index.htm
I'll update this list as I find more usefull info