In astral projection, the human soul allegedly leaves the body to journey to other places, usually to communicate with the spirit realm, to get one step closer to godhood (Eckankar). Participants usually say they are conscious during the experience, and are able to feel physical sensory sensations. The process is a means of spiritual purification.
Some in the church have accepted the practice as holy. One woman once told me, and she was a pastor's wife!, that during her sleep, the Lord was allowing her to astrally project to a country behind the iron curtain to minister to a Christian woman who was oppressed by the government there.
The Bible in no way condones the practice of astral projection. In fact, the Bible tells us that our soul leaves our bodies at death (Genesis 35:18), and that we will be perfected at our resurrection (1 Thessalonians 5:23)...not by journeying to other realms and conversing with spirits (demons).
We are, also, told that we must accept that we have limitations of knowledge in this life (1 Corinthians 13:8-12), and that we will know more when we see God face to face! Many Christians are torn over whether or not astral projection is hallucinatory or real. Having not ever astrally travelled, I can't say which is correct. However, either way, there is a spiritual danger involved -- willfully desiring to leave one's body weakens the will, leaving one susceptible to demonic intrusion, which would allow demons to enter the body, a form of spiritual possession that even some Hindu yogis acknowledge). Is it New Age, or Old Lie? The Bible would indicate that it is just one of the many ways satan would seduce those who are seeking God.