As I type this, these Kindle books are free but they probably won't be for long. They may or may not be much but they're worth every penny or more...maybe. ;) Descriptions from the Amazon listings, Kindle not required.

The Chromatic Scale (Guitar Theory Made Easy)
-- this is the first in the Guitar Theory Made Easy series of short guides aimed at helping you get your head (and fingers!) around music theory, and applying it MUSICALLY on your guitar.
http://www.amazon.com/Chromatic-Scale-Guitar-Theory-ebook/dp/B00DP16IWU/ref=sr_1_2?s=digital-text&ie=UTF8&qid=1372553538&sr=1-2&keywords=guitar+instruction

Guitar Instruction For The Not So Serious Guitar Player (Learning Guitar Without Learning To Read Notes Or Formal Tabs)
-- one needs to change ones understanding about guitar practice and forget about becoming a "Guitar Hero". With this new philosophy of guitar instruction the author lays down the fundamentals of basic rhythms, chords and scales within the scope of Blues, Folk and Classical guitar.
http://www.amazon.com/Instruction-Serious-Learning-Without-ebook/dp/B009LVJMU8/ref=sr_1_1?s=digital-text&ie=UTF8&qid=1372553624&sr=1-1&keywords=guitar+instruction

The Absolute And Utter Beginners Guide To Learning To Play Guitar (Focus On How To Play The Guitar)
-- a book for the total newcomer to learning to play guitar.
http://www.amazon.com/Absolute-Beginners-Learning-Guitar-ebook/dp/B00BSEGTN4/ref=sr_1_3?s=digital-text&ie=UTF8&qid=1372553624&sr=1-3&keywords=guitar+instruction