The Third Step Prayer is found on page 63 of The Big Book, the Basic Text for Alcoholics Anonymous. The text is as follows:
"God, I offer myself to Thee-to build with me and to do with me as Thou wilt.
Relieve me of the bondage of self, that I may better do Thy will.
Take away my difficulties, that victory over them may bear witness to those I would help of Thy Power, Thy Love, and Thy Way of life.
May I do Thy will always!"
This prayer is recited by a person who is working on their recovery from alcoholism after they have completed Step One and Step Two of the Twelve Step Program. Steps one and two consist of an alcoholic admitting to herself that she is powerless over alcohol and can't manage her own life, and that a higher power could restore her to sanity. When those two beliefs are reached, the alcoholic is ready for Step Three, which consists of turning her life over to the care of that higher power. That's what the prayer is all about.
The wording of the Third Step Prayer can be and often is changed to fit the needs and beliefs of the person doing the praying. Alcoholics Anonymous doesn't require anyone to believe in any certain God or religion. Indeed, many alcoholics who come into the program are so disillusioned and wounded by life that they are agnostic. The only spiritual belief that is required is for the alcoholic to believe in a power greater than themselves. The power needn't be defined nor understood. Grandmother, Goddess, Grandfather, Allah, Fred, Hey You, or Nancy can be substituted for the word "God" in the prayer and the results are the same, as long as the prayer is willing to hand over their life and their will to that entity.
On a personal note, I had real trouble when it came my time to say the Third Step Prayer for the first time. I had problems with all of the "thees" and "thous" and "thys" because I really struggled with the whole Biblical Christian God thing. My sponsor (the person who guides an alcoholic through the twelve steps) had me write my own prayer, using any words I wanted, just so long as I was indicating that I wanted to hand over my life and will to my higher power. It was still hard to do, but I did it and it was an important turning point in my recovery.