Swami Parthasarathy has written many books. If we read these we will get an overall idea.
We can also read his Bhagavad Gita book.
He runs Vedanta Acadamy in pune. His students conduct free classes all over the world (Bhagavad Gita , vedanta etc).
This is the link to the site of the Acadamy – http://vedantaworld.org/
This is the link for the classes in India – http://vedantaworld.org/studyindia.asp
This is the link for the classes abroad –http://vedantaworld.org/study.asp
In addition, the woods of self realisation by Swami Rama tirtha is very good. This is available as a free download.This is the link for the free download – http://www.ramatirtha.org/freebooks.htm
I attend the Bhagavad Gita classes conducted by Mr. Lakshmi Narayanan. He is a student of Vedanta Acadamy. This is the audio link of my classes http://www.sriananda.in/download.html. This site has upto chapter 3 so far. As the class progresses we will update this link.
I hope this will be useful for my blog followers. If I come across any other good book or sites – I will update in this post.