I get weird sensations when I meditate, like having my sensation of my hands/arms 'fade out', or seeing waves of purple light, or feeling as if I'm 'moving around inside myself'. From what I've read on the subject, I'm sure I must be achieving some sort of altered state...
I'd suggest not worrying too much about assuming a special posture. I have often done my sessions lying flat on my back, and they work out just as well.
LF, about your sig line - when I first starting trying to apply IM techniques, I'd constantly remind myself not to put the cart before the horse. Some time later I realized my error, and revised the reminder: "There is no cart, there is no horse. There only IS."
