I've known several people who had great experiences with AA, but if you're looking for a secular alternative, they are out there. SOS (Secular Organizations for Sobriety/Saving Our Selves) is one of them, and Rational Recovery is another. I don't know about their success rate (long- or short-term) compared to AA, but perhaps other people know about them, or about other groups if AA is not for you.
http://www.sossobriety.org/
http://www.rational.org/