Attunement is the process by which the Master opens the initiate's
crown, heart and palm chakras along with their third eye and throat
chakras to pass on the technique of Reiki to the initiate and forge a
link between the everlasting Universal Energy and the recipient.
Reiki Attunement is an extremely spiritual experience by responding
to the voice of the Divine Spirit within. You are attuning yourself
with the energies of the Universe and releasing your intention to the
Universe to be a healer and a medium to channel the positive
vibrations of Light and Love.
An attunement makes a person more psychically sensitive and
facilitates the channeling of greater amounts of Reiki energy.
After the Attunement all the natural centers of energy in the body
star to vibrate at very high frequencies and open the recipient to a
field of Higher Consciousness and sensitize the initiate to messages
from Reiki spirit guides and angels during the process of Attunement.
An attunement is a life long gift that can never be lost or diminish;
it is always contained in the heart and spirit of the recipient as a
gift of love, life and laughter. And this gift keeps multiplying each
and every time you channelise Reiki energy and spread Love and attune
yourself with the Higher Powers....

More About Reiki: http://groups.yahoo.com/group/reikijenf