The links below should help you out in your research. There are general links that address all the organs together and there are some specific sites for individual organs. Please make sure that you do NOT copy any information word for word. All information written down should be rewritten in your own words.
Body Thinkquest (loads of information)
How the Nervous System Interacts with Other Body Systems
Gross & Cool Body - Skeletal System
Gross & Cool Body - The Cardiovascular System
Gross & Cool Body - The Digestive System
Gross & Cool Body - Endocrine System
Gross & Cool Body - Muscular System
Gross & Cool Body - Nervous System
Gross & Cool Body - Respiratory System
Gross & Cool Body - Urinary System
The Heart -- An easy-to-read, but descriptive outline of the activities of the heart, can be found here. A basic diagram is also provided.
Kidneys -- A clear, basic diagram, accessible glossary for difficult terms, and an excellent description of the kidneys' activities, can all be found at this site.
The Brain -- A general diagram and description of the brain can be found here.
The Lungs -- An in-depth description of the role of the lungs in the respiratory system is given in this site. A good description of a lung's structure, and a basic diagram are included as well.