This page contains information about Astral projection and astral travel.
It is sometimes attempted out of curiosity, or may be believed to be necessary to, or the result of, some forms of spiritual practice. It may involve "travel to higher realms" called astral planes but is commonly used to describe any sensation of being "out of the body" in the everyday world, even seeing one's body from outside or above. It may be reported in the form of an apparitional experience, a supposed encounter with a doppelgänger, some living person also seen somewhere else at the same time.
Below are some links in which I think offer some decent material worth reading relating to the subject.
http://paranormal.about.com/od/outofbodyexp/OutofBody_Experience_Astral_Travel.htm
