Wikimedia
Wikipedia: Gastrointestinal Tract
Wikipedia provides excellent resources and information on the gastrointestinal or digestive tract, including images and hyperlinked terms.
Inner Body
Innerbody: Digestive System
Take a look inside the human body's digestive system. This site features diagrams of the digestive tract and each part is accompanied by labels and descriptions. Just select an organ by moving the mouse over its image.