http://www.weather.com/outlook/health/fitness/tools/calorie

Type in your weight, select the activity, and type in how long you plan to do that activity.. and it gives an estimate of how many calories you'll burn.

I just found this and thought it was pretty cool. (:

 This is a standard feature in MyFitnessPal and most food logging journals as well.

I added that to my favorites in case I'm curious before a lunchtime walk.  That's pretty neat.

If you've never seen it, there's a little gadget called a bodybugg that sits on your arm that measures how many calories you're burning all the time.  It has all kinds of neat charts and graphs that it will put together, and a food diary so you can keep a running total of intake vs. output, and make sure that you're running at a calorie deficit all the time.

That's a great tool.  I use MFP and my fitbit page, but  it's always nice to have extra options.

 I **HIGHLY** recommend a heart rate monitor. I used to use all those calculators and went off what the machines told me I was burning.

I got my HRM (A Polar F6) and HOLY COW those estimates were waaaaaaay off!