If the thought of the "Serenity Prayer" as a prayer bothers you, try thinking of it as a meditation instead. The concept behind the prayer is very valid for many alcoholics. Essentially you are asking for guidance in being able to accept life on life's terms and not trying to control every situation, like we frequently did while ill. There is no requirement that you include the words "God" and "Amen."
I, for one, can attest to the fact that the seeming lack of control over everything in my life contributed greatly to my drinking. Frankly, it is the Serenity Prayer that has really helped me get to Day 26, despite some serious losses I've sustained lately because of my past drinking.
Also check out the secular alternatives to AA as pointed out in previous posts.