Yoga Nidra is a state of conscious Deep Sleep.
In Meditation, you remain in the Waking state of consciousness, and gently focus the mind, while allowing thought patterns, emotions, sensations, and images to arise and go on. However, in Yoga Nidra, you leave the Waking state, go past the Dreaming state, and go to Deep Sleep, yet remain awake. It’s refreshingly restorative!
Try these websites for more info
http://www.yoganidranetwork.org/This site offers FREE Yoga nidras, as well as information on workshops
Offers an insight into Yoga Nidra.
Wishing you all, all the best, thanks