Here are a few good web resources that I have used:

MSKCC.org
"Treatment, Research & Education: Since 1884, Memorial Sloan-Kettering Cancer Center has been dedicated to improving the understanding and treatment of cancer. Their dedicated team of professionals is committed to providing The Best Cancer Care. Anywhere." This site is good for nutrition and cancer therapy. It also provides some information on herbs.

Dianadyermsrd.com
AKA: CancerRD.com - This site is created by Diana Dyer, M.S., R.D., a dietitian and a breast cancer survivor. Her mission is to provide information and inspiration for cancer survivors regarding nutritional and lifestyle choices that promote the extension and quality of their lives. Her site provides great links, too!

Naturaldatabase.com
A subscription based site designed for medical professionals. It also provides a separate website for patients /consumers. This site is the gold standard for evidence-based, clinical information on natural medicines. It is the most complete and up-to-date reference available.

Consumerlab.com
Their mission is to identify the best quality health and nutrition products through independent testing. Some parts of this site is available without a subscription, but a subscription is needed for online access to the complete CL Products Reviews.

Cancer.gov is the home of the National Cancer Institute.
The National Cancer Institute coordinates the National Cancer Program, which conducts and supports research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer, rehabilitation from cancer, and the continuing care of cancer patients and the families of cancer patients. This site provides a wealth of information for all who visit.

Cspinet.org
The Center for Science in the Public Interest. Since 1971, CSPI has been the premier nutrition advocacy organization. They publish the award-winning Nutrition Action Healthletter, the largest-circulation health newsletter in the country.

Quackwatch.com
A very good site that is updated regularly, Quackwatch is your guide to health fraud, quackery and intelligent decisions. Operated by Stephen Barrett, M.D.

Mayoclinic.com
A well organized site that provides "Reliable information for a healthier life." The home page provides topics of interest and features as well as a way to look up information quickly.

Medlineplus.gov
Offers health information such as Current Health News, Featured Site, In the Spotlight, a Medical Encyclopedia, a medical Dictionary, links to Other Resources and more.

Nccam.nih.gov
The National Center for Complementary and Alternative Medicine. Their mission is to support rigorous research on complementary and alternative medicine (CAM), to train researchers in CAM, and to disseminate information to the public and professionals on which CAM modalities work, which do not , and why.

Aicr.org
American Institute for Cancer Research believes that most cancers can be prevented, And reducing cancer risk may be easier than you imagine. AICR provides news, research updates, recipes, free publications and tips for good health - information to help you live a healthier, cancer-free life.

Nutritionfocus.com
"Your Complete Source for Nutritional Information." Among other topics, the visitor can find information on Nutrition/Supplementation, Food Facts & Recipes, Life Cycles/Lifestyles, Gender Health, Exercise & Nutrition, Health News Online and Integrative Medicine.