Yes the Atkins plan really works if you follow the rules and like any diet, eat what you're supposed to and exercise.
The difference is on this diet you will generally feel very full and satisfied due to high fat content, and if you are able to break the addiction to carbs, you will feel a whole lot better as well.
Again as with other diet plans, this is not a "diet" and if you return to eating the way you did before you will most surely gain the weight back (as you have experienced). You need to consider this as a lifestyle change and ensure you can follow this woe for a very, very long time.
I would highly recommend you get the book (Dr. Atkins New Diet Revolution) and read it cover to cover before starting, paying special attention to the section on Induction. You may also visit www.atkins.com
to get an idea on the four phases of the diet and get more information on acceptable foods.
Good luck and let us know what you decide. We are always here to answer questions and provide support!