I don't know what do you mean by simple, but Kline's book is a good introduction (for social scientists) http://www.amazon.com/Principles-Practice-Structural-Equation-Methodology/dp/1606238760

Barbara Byrne's book "Structural Equation Modeling with Amos" should be a good choice: http://www.amazon.com/Structural-Equation-Modeling-AMOS-Applications/dp/0805863737

As Crhistoph suggested, Barbara's book is very simple to follow, specifically for using AMOS. The book also provides data set in its companion website which is very useful for the beginners to follow the step-by-step process for analyzing the data using a single data set.

If you need a copy, feel free to inbox me.

To start learning about SEM, I suggest for you to read the designated chapters first in Adv. research or statistics books. you will find the presentation not complex and can be understood. good luck.

I am attaching an article which used SEM 

If you do a search on google for "free" and than add the name of the book (i.e strucutral equation model" you might be able to find a good itroductory book. This information was passed on to me by students

This is simple book, but I think not available online.

Structural Equation Modeling Zainudin Awang

I think this is a good one

I also recommend 'structuraluation Modeling' by Zainudin Awang

Burns， B. (2010). Structural Equation modeling with amos. Basic concepts，applications， and programming. New York: Routkedfe.

Make a search using “free” and you might find parts of the book for free.

It is an excellent book for someone willing to start and very helpful for those in more advanced training in SEM

GOOG LUCK

You can see the following review paper about SEM:

http://pubs.sciepub.com/amp/5/3/2/