I'll leave it as an exercise for the reader to make up their own mind on the legitimacy and effectiveness of such practices. I think, like any practiced meditation, it is a matter of deep personal preference whether one sees through the mysticism or is stopped short by it.
[1] http://en.wikipedia.org/wiki/Astral_projection [2] http://en.wikipedia.org/wiki/Astral_plane
I don't know if I've every astrally projected, but have met many spirits, who are just people (albeit non-physical) in what I call the spirit world. I don't see it as mystical. I try to keep an open mind about what the reality is (i.e. all in my head and dead is dead, or we're part of something larger and immortal) but lean toward immortality.