I've got my reservations about this. You bring up the Biblical explanation, but nowhere does it say anything about leaving your body to fly around.
Second, do you know who these "guides" are?
Third, if you believe in Angels, Demons, Ghosts, etc... then what's to say that when your consciousness, or soul, leaves your body, that something else doesn't take it over while you're on holiday?
It all seems like a nice change from day to day monotony, but it's also a very dangerous thing. Although
http://en.wikipedia.org/wiki/Astral_projection uses the same Biblical reference as you do, it is taken out of context. The use of "in the spirit" has nothing to do with astral projection. It's referring to the Holy Spirit, praying in the Holy Spirit. The trance is related to just that, and not leaving your body.
Astral Projection has been studied extensively, and it's authenticity is still inconclusive. It is believed by some to be real, and by others to be psychological, lucid dreams, etc... Personally, I've had some VERY vivid dreams that felt too real to have been just dreams. I've felt like I've fallen back into my body and jolted awake. Does it mean I've left my body? Absolutely not. It just means my imagination (a dream) created a sense of falling. It's pretty easy to explain, considering that when you're awake, and someone touches your arm, you feel it. But when you're asleep, you can slap some people in the face and they won't wake up, they don't feel it, and have no recollection of it in the morning. Your brain is fully capable of tuning off some senses and creating others within itself, which in turn can create a false reality. Whether it be when you're asleep, or when you are in a traumatizing event. Everyone has their own set of triggers.