It is pretty hard to gauge how many calories you burn from activity. You could trust tables like this:
http://www.nutristrategy.com/activitylist4.htm

But who knows how much they apply to a given person.

There are companies like BodyMedia which make medical devices that strap on your arm and glean everything they can. It’s a big sensors and machine learning problem. Apparently they can get a live estimate of the rate at which you’re burning calories, along with dozens of other numbers.

Unfortunately, like any smart company, they are targeting high-end patients like those with insurance and heart problems.

For those of us who’d like to know exactly how many calories we burned in a day, but don’t want to spend thousands of dollars, there seems to be no gadgets available…

WAIT … as I was writing this comment, I found this:
http://www.bodymedia.com/products/bodybugg.jsp

$499 for the “BodyBugg” by BodyMedia. Horrible name, but apparently it’ll track your calorie burning rate & has web tools to upload that info plus food consumption and all.

Phil, you should totally see if your insurance would cover it. I’d certainly like to see someone’s recommendation before I buy something like this. Excellent gadget though.