WebMD - Gas, Bloating and Burping - http://www.webmd.com/heartburn-gerd/tc/Gas-Bloating-and-Burping-Topic-Overview Find information about causes and treatments.
Introductory Anatomy: Digestive System - http://www.leeds.ac.uk/chb/lectures/anatomy8.html A complete look at the this system starting with the purpose, mouth, swallowing, oesophagus, stomach, duodenum, small and large intestines, salivary glands, pancreas, liver and gallbladder.
Focus on Digestion - http://www.aboutdigestion.com/ Features news, clinical trial and articles.
eMedicine Health - Abdominal Pain in Children - http://www.emedicinehealth.com/Articles/9810-1.asp Consumer health resource center providing an overview of a tummy ache and its causes, symptoms and treatment.
Principal Health News - Digestive Center - http://www.principalhealthnews.com/topic/digestivecenter Digestive disorders center for help with intestinal problems, from common disorders like flatulence or heartburn to less common ones such as Crohn's Disease or gallstones.
Radiology Info: Upper GI Radiography - http://www.radiologyinfo.org/en/info.cfm?pg=uppergi Information about the procedure. Explains what patients might experience, how to prepare, and benefits versus risks.
Gastrolab - http://www.gastrolab.net/welcome.htm This site is dedicated to digestive disorders. Chat and a mailing list available for support.
Digestive Disorders - AOL Health - http://www.aolhealth.com/condition-center/digestive-disorders Describes the symptoms, diagnosis, and treatment options.
NIDDK: Digestive Diseases Diagnostic Tests - http://www.niddk.nih.gov/health/digest/pubs/diagtest/index.htm Patient education fact sheets on six diagnostic tests involving gastrointestinal disorders: colonoscopy, sigmoidoscopy, upper GI series, lower GI series, upper endoscopy and ERCP.