There is a good book on the subject of astral travel called "Astral Dynamics" by Robert Bruce. I havent gotten throgh the entire book yet (school takes up pretty much all of my time) but so far the stuff seems very, very interesting. He pretty much gives a step by step guide on how to astral project, stories about his projections, as well as steps for developing your chakras.
He also has his own web site: http://www.astralpulse.com/index.htm
Another cool book is "The Holograpic Universe" by Michael Talbot. I can't even begin to describe this book. It's insane, you must check it out and experience it for yourself!!
