Innerbody.com
Check out this side view of the movement of the diaphragm and ribs during breathing. This site has this and many other animations and stills.

Calories Burned During Physical Activity
This site shows a list of common activities and the number of calories burned per hour while performing these activities.

Calories and Exercise
Find out how many calories you can burn during specific exercises.

Good Housekeeping Diet Central
This offers a database in which you type in the number of minutes spent doing a specific activity to determine the number of calories burned.

An Unlikely Exercise for Burning Calories
Find out about the benefits of walking as an aerobic exercise for burning calories.

The Heart Preview Gallery
Want to know more about your heart? Organized in five sections--do, see, learn, go, and hear--this site incorporates the latest audio and video technology.

American Heart Association
Find out more about your heart and diseases that can affect it. The site also contains information about how to maintain a healthy heart.

The Electric Heart
Check out this site, which allows you to perform your own heart transplant. Also, see through animation the flow of blood through the heart.