There are many uses of the all powerful Gayatri Mantra, so you should certainly not be surprised that there is also a Gayatri Mantra Meditation, for helping to open the all important Third Eye Chakra.
As with all such powerful meditations, I suggest not to overdo it and build up your capacity slowly over time. There are many reports of the effectiveness of this meditation both in the spiritual literature and in the personal experience of people I know, so do this meditation with great respect and devotion. If you do acquire psychic powers as a result, please use them only for your spiritual growth or to help others.
-Helps to Open and Balance the Third Eye Chakra.
-Increases intuitive abilities and psychic powers.
-Bestows peace and tranquility.
-Helps promote spiritual growth and inner communion.
-Builds concentration and mental focus.
Here is the Mantra used in the Meditation and the Translation:
Om Bhur Buvaha Svaha
Tat Savitur Varenyam
Bhargo Devasya Dheemahi
Dhiyo Yonaha Prachodayath
O Supreme Creator, Thou art the giver of life, the remover of pain and sorrow and the bestower of happiness; O Creator of the Universe, may we receive Thy supreme sin-destroying light; may Thou guide our intellect in the right direction.
Sit in any cross legged posture. You can also do this meditation sitting on a chair.
Elongate your spine and tuck your chin in slightly (like a soldier at attention). Bring your hands in Gyan mudra, which is to have the thumb tips and index finger meeting. Then, rest your wrists gently on your knees, with your palms facing slightly upwards.
Close your eyes and turn them upwards such that you looking through the center of the forehead. This is Shambhavi mudra, and only hold it for as long as is comfortable. Release it whenever necessary and continue with the meditation, reapplying it when ready.
Next begin to mentally chant the Gayatri Mantra, while visualizing it emanating out from the Third Eye Chakra Point.
Continue to chant the mantra silently for the duration of the meditation in this way. You can do this meditation for as long as you like. Start with 3 minutes and build up from there.