There are many reported effects of it. The effects that happened to me are OBE, Future "sights", slipping in and out of what I would call a different ...hmmm universe? multiverse? Has different effects on different people. /ttiforum/images/graemlins/yum.gif
Psychedelic drugs can definately give you a snap shot of extra sensory conditions. The do however rip big holes in your astral "body". This has been told to me by experienced psychics.
So while drugs can have a beneficial effect in terms of providing experience of other dimensions, long term use can lead to problems protecting yourself astrally.
It is much safer to use mediation, and once achieved, you will be able to maintain astral states and not just get uncontrolled glimpses. All humans have the ability to adjust their rate of vibration sufficiently to be aware of their astral form. Drugs are counter-productive if you wish to do this from a point of view of raising your vibrational level permanently. There is no short cut to this, other than complete and utter self-realisation. Budha only achieved self-realisation afer many many years of meditation and suffering, although the moment of realisation itself is I think instantaneous.
That's not to say drugs have no place in entertainment, or even for inspiration while writing or contemplating life. But they are probably best used occasionally, rather than to rely on them for spiritual growth, which can only come from inside.