EllaDell

Pocket Diet Tracker keeps a running total of your Carbs (also Protien and Fat) in grams (and also as a percentage of calories consumed) you can also set goals and warning for if you for example go over your goal for the number of grams of carbs for the day. I believe that probably some of the others that are not specific to a certain diet such as Pocket Diet would be similar.
Under the rules of Atkins I think that you can subtract out grams of fiber from the total number of carbs and use that number towards your offical daily total. I am not sure that anything but an application designed especially for Aktins (or similar low carb plans) would do the subtracting out of fiber for you. I think that I have seen application specifically for that purpose on Handango or other sites, just search for Atkins, low carb or low carbohydrate.