Ok, I saw a few reply's on the first page, and I'm gonna tell you what I know about Astral Projection. I am an avid Metaphysics practitioner (Astral Projection, Aura's, Empathy, Energy Manipulation, you can google all of those) and this is what I know about Astral Projection. First Stage:
Out of Body Experience: This is when your soul leaves your physical body for a time, and you are able to move around on this plane, do things on this plane, all the good stuff. And it's all in the same perception of time...meaning? It means, that if you set up an experiment to try an out of body experience, and you have a person in another room doing something (watching a movie, playing a game, reading a book etc...) you'll be able to see them, with a few added perks. When you're soul is out of body, you're on what's known as the Etheric Plane. It's the plane of existence between the physical plane (the one we are on) and the next plane (Astral Plane). The Etheric Plane is commonly a place where other spirits, or apparitions such as ghosts mainly "Spend their time" because I can't say they live there, it'd be a horrible pun. On this realm, you're soul can fly, you can basically think of a place you want, and if you concentrate hard enough you'll be there. You can walk around normally, but sometimes you don't feel the ground. Sometimes you'll feel pain, other times you won't...it's very weird.
Second Stage...
Astral Projection: This is where you project your soul to the second realm (there are a total of seven, you can search for the list on a metaphysics site, like
http://www.astralsociety.com) This is a very....interesting realm. It contains the "Astral Library" a library with books on most everything past and present, along with a fair amount of things on the future (don't wanna say everything on the future cause I'm not sure of that). Here is where other spirits live, demons, angelic figures, spiritual guides that can communicate to us on out physical realm, etc. Somebody made the comment "Why a higher plane, why not a lower plane." Well here's an answer to that, when you go to the astral plane, there's different "vibrational states", low, middle, and high. The vibrational states depend on a persons energy output, and intent. You can visit any that you want to, it just takes a little doing. The lower level is commonly where the demons and malevolent spirits exist at...sort of like hell, except nowhere near it.
I'll be glad to post more if anybody wants to know. I'm also open to talking to healthy skeptics. If you don't believe me, try it for yourself, and tell me what happened to you.