Hi Sara. To try to answer your question...
AA is a program for alcoholics. You attend meetings, work with a sponsor (someone who kinda becomes your mentor through the program) to work through the 12 Steps of AA as outlined in the Big Book of AA. If you would like more information on the steps and how the program works more specifically, you may want to ask your question on the Alcholism board. One of the major principles of AA is that it is a "spiritual" program, and that is one of the things the steps help you with, discovering or even redefineing your spirituality. While it is not a "religious" program, the word god is frequently used to define the higher power that it is suggested you "turn your will and life" over to.
I have been to many AA meetings, but have never really "worked the program". (ie: got a sponsor, worked the steps, etc.) I'm sure there are many others who can go into the program in greater detail if you wish, but as nobody seemed to be doing that, I figured I'd give it a shot.
AA is not the only "program" available for alcoholics looking for help, however it is the most well known and most widely available for in person support. A few other programs you might want to look into are SMART, Lifering, SOS and Rational Recovery. A quick google search will turn up all kinds of information about those programs.
As far as rehab goes. As was mentioned, there are basically two types, inpatient (where you actually reside at the treatment center 24/7 for a period of time) or outpatient (where you have group support meetings, therapy sessions, the teaching of coping skills, etc. Usually you will meet between 3-5 days a week for between 1-3 hours, sometimes more depending on the program)
The information you learn in either kind of rehab is very similar. Often it is based on 12step recovery (ie:AA) but not always, and usually not exclusively. The biggest difference is obviously the amount of time involved in the program. Some people find outpatient better as it "takes them out of circulation", so to speak, for awhile and they can establish some sober time while at the rehab center. Inpatient is definately a more "intense" experience as your life becomes very structured, whether you want it to be or not. Most people with substance abuse problems tend to lack structure in their lives and often have to "relearn" how to live. A typical day will consist of a number of "classes" where you learn about your alcoholism and how to cope with it, usually a group therpy session, sometimes some individual therpy sessions, and often an AA or NA meeting in the evening. You are kept busy, usually about 12 hours a day. Bordom is the enemy of the addict. Every rehab is different, but the same. Some are fancy, some are very bare bones, but you will basically learn the same things at all of them.
Often there are state funded substance abuse clinics you can receive help from. The offer counciling, group therpy, and recovery classes for little or no money. You can contact your local social services department for information about that.
As far as myself, I've been to inpatient rehab twice, outpatient twice, a lot of meetings, been here at SR for years, studied dozens or recovery methods and books, and after 20+ years of using only now have about 8 months of clean time. I guess my point with that is that no program, rehab, doctor or anyone else can stop you from drinking. They can all give you tools to help you, but you are the one who has to make the decision to actually put the work into stopping, and it is work!!
I hope this answers some of your questions. I know the desperate place you are right now. Nobody is telling you what you want to hear, that being "how do I stop drinking". The reason is that there are as many ways as there are people with drinking issues. All anyone can do is give you suggestions, you are the one who has to follow them, and decide what works best for you. I understand how you ******* hate your life right now. I thought I was a hopeless addict for the longest time, but I now know better. It hasn't been easy by any means, and I'm still new at the whole "clean and sober" thing. It does get better, but you have to make the decision to take back control of you life. You can do it. Take care.