Walk Away the Pounds tapes

Impossible to give you an answer. It depends on your walking speed, your weight, the incline. There are just too many variable to answer this question with any accuracy.

You can try using a pedometer a judge more accurately. I was able to find one in the app store that's free and tracks distance walked, steps taken, average speed, and calories burned.

Here is a calculator for you: http://www.sparkpeople.com/resource/calories_burned.asp?exercise=58
If you want accurate figures, buy a heart rate monitor (chest band) like this one: http://www.amazon.com/Polar-Bluetooth-Smart-Heart-Sensor/dp/B007S088F4/

Leslie Sansone has mentioned on a blog post here at MFP that you can use the "aerobics, general" choice when logging exercise here at MFP. Granted that isn't going to be as accurate as a heart rate monitor, as amayitux suggested. The calories burned as listed on MFP or any website are just guidelines based on your height and weight, but not necessarily effort. Although better guidelines that most gym machines show (since those are typically based on what a 150 lb woman who is 5'5" would burn - or some such nonsense).

It all depends upon how much effort you put forth. You know, if you are going all out and using a wide range of motion compared to barely lifting your feet to move, you will burn more calories. The heart rate monitor is showing specifically what YOU burned.

I love Leslie's workouts. They were my "go to" for exercising at home this winter. Now that the weather is nice again, my dogs are my "go to". (Plus my two 15-minute walks at work.)

Not sure if you are aware of this, but there's also a Leslie Sansone group that you can join on MFP:
http://community.myfitnesspal.com/en/group/335-leslie-sansone-walk-at-home