Here is one that I attended which anyone can attend. It is primarily geared toward law enforcement, but many people go to it. It teaches the nuts and bolts of effective communication, both how to communicate with others and how to keep them communicating with you.

http://www.analyticinterviewing.org/

People the world over are much more alike than not. We all have our preconceived notions, but they rarely hold true when faced with reality.

Dale Carnegie's book is the one to read if you have no others. There are others and I will look for titles. Having an understanding of how the human brain works helps. Dr. Paul Ekman has done a lot with reading facial expressions; and if you can read those accurately, you can know when someone is hiding something. Here are his two principle works:

http://www.amazon.com/Emotions-Revealed-...8507&sr=8-1

http://www.amazon.com/Telling-Lies-Marke...8507&sr=8-4