With todays technologies that are available, I suggest that you go to the web and Google something like "Calorie Counter", and then pick one you like.
I personally, have an iPhone, and one of the most popular Apps is the free app called LoseIt.
I use it daily, to track my caloric intake, as well as other key nutrients, utilizing its database. With it, I can enter any food I eat at any time and anywhere.
And the good thing is that I have a nice ongoing summary of my Calories, Fats, Saturated Fats, Carbs, Cholesterol, Sugars, Proteins, Fiber, and Salt, in one handy table.
As a further testament to the iPhone and App combination, I have lost over 40 pounds over the past four months, just by making myself concious of what I ate and where.
If you do not have an iPhone, the same app works on an iPod, I believe.
And, actually, there are a number of applications for other smartphones and pod-type devices.
Just shop around.
And ...... Good Luck.