Most of the plans do not encourage counting calories. Personally I have found that they do matter -but being in ketosis stops you feeling hungry and you usually end up eating less calories. Calvin Ezrin in "Your Fat Can Make you Thin" does advocate counting calories - he recommends 1000 per day for rapid weight loss together with 30g carbs. I think it really depends on which plan you are following.

I really recommend you get one of the books and read the theory it is very worth while. You can check the different plans here where there have been some useful write ups of them. Click on 'which plan is right for me?'