It can also be used as a precursor to the lucid dream state or to an out-of-body experience since both are more easily achieved when both mind and body are calm and open to new experience.
One great help in all of these states is music, and especially when it is designed to relax us and induce an altered states of consciousness. We’ve just found a great source of both this kind of music and some great articles on using it for meditation. It’s called the Meditation Music Blog! at http://www.hemisyncforyou.com/
Enjoy your explorations and the beautiful music!