I would think, since you're doing Atkins, that it would be pretty easy to "self-modify" your food in most restaurants, regardless of whether or not they offer specifically LC entrees. If you order a burger, take off the bread, and get veggies or a salad on the side instead of french fries. Order grilled meats, poultry, or fish and again, stick to veggies on the side. You know what you can and cannot eat, so just order accordingly! Explain to your server that you're doing Atkins, and they should be able to help guide you in their establishment's menu specifically (not to mention keeping the bread off the table!) But, ultimately, I would think you would be able to make ordering decisions fairly easily, since you don't have the caloric restrictions that low-cal'ers have, for instance.
I always say, where there's a will, there's a way!