Here's a partial list of books to check out that I've found particularly helpful on the road to exploring Buddhism, spirituality and the 12 Steps of Recovery (note that not all of these are related directly to the 12 Steps):
One Breath at a Time: Buddhism and the Twelve Steps by Kevin Griffin
A Burning Desire: Dharma God and the Path of Recovery by Kevin Griffin
The Spirituality of Imperfection: Storytelling and the Search for Meaning by Ernest Kurtz and Katherine Ketcham
Dharma Punx: A Memoir by Noah Levine
Against the Stream: A Buddhist Manual for Spiritual Revolutionaries by Noah Levine
The Heart of the Revolution: The Buddha's Radical Teachings on Forgiveness, Compassion, and Kindness by Noah Levine
The Noble Eightfold Path: Way to the End of Suffering by Bhikkhu Bodhi
12 Steps on the Buddha's Path: Bill, Buddha, and We by Laura S.
The Sound of Silence by Ajahn Sumedho
Mindfulness and the 12 Steps: Living Recovery in the Present Moment by Therese Jacobs-Stewart
Buddhism Without Beliefs: A Contemporary Guise to Awakening by Stephen Batchelor
Living with the Devil: A Meditation on Good and Evil by Stephen Batchelor
Confession of a Buddhist Atheist by Stephen Batchelor
All of Jack Kornfield's books
All of Joseph Goldstein's books
All of Sharon Salzberg's books
One Breath at a Time: Buddhism and the Twelve Steps by Kevin Griffin
A Burning Desire: Dharma God and the Path of Recovery by Kevin Griffin
The Spirituality of Imperfection: Storytelling and the Search for Meaning by Ernest Kurtz and Katherine Ketcham
Dharma Punx: A Memoir by Noah Levine
Against the Stream: A Buddhist Manual for Spiritual Revolutionaries by Noah Levine
The Heart of the Revolution: The Buddha's Radical Teachings on Forgiveness, Compassion, and Kindness by Noah Levine
The Noble Eightfold Path: Way to the End of Suffering by Bhikkhu Bodhi
12 Steps on the Buddha's Path: Bill, Buddha, and We by Laura S.
The Sound of Silence by Ajahn Sumedho
Mindfulness and the 12 Steps: Living Recovery in the Present Moment by Therese Jacobs-Stewart
Buddhism Without Beliefs: A Contemporary Guise to Awakening by Stephen Batchelor
Living with the Devil: A Meditation on Good and Evil by Stephen Batchelor
Confession of a Buddhist Atheist by Stephen Batchelor
All of Jack Kornfield's books
All of Joseph Goldstein's books
All of Sharon Salzberg's books