There are a tremendous number of online resources that give guidance on how to talk to children about cancer. The vast majority are focused on adult cancers, but a few address pediatric cancer. I have selected several great resources below. Please send information about additional resources to firstname.lastname@example.org, particularly resources focused on discussion pediatric cancer with children.
This is an excellent website from the American Brain Tumor Association. The website is developed for children to use on their own, or with a parent. Clear language, not intimidating. Asks and answers questions like: What happens when someone has a CAT or MRI scan? Do you feel anything? http://www.abta.org/kids/index.htm
Broad children's health website from Nemours, with a cancer specific section. This section about targeted at friends of children with cancer is very well targeted: http://kidshealth.org/kid/cancer_center/feelings/friend_cancer.html "Everyone knows that doctors are really important when a kid has cancer. But did you know that friends are really important, too?"
The website also has sections about: Cancer Basics, Treatment & Prevention, Dealing With Feelings, Diagnostic Tests, How the Body Works, Personal Stories, General Q&A, Cancer Words to Know and a whole bunch of information in Spanish (En Espanol section). http://kidshealth.org/kid/cancer_center/index.htmls
And - for teens, a similar site: http://kidshealth.org/teen/cancer_center/index.html
From way Down Under, this electronic book (PDF) is really great. It has sections targeted to different age groups (e.g. 3-5 years old). It is target at talking to children about adult cancer, as are most resources on the web.
For a great program and information about children with cancer and the challenges related to school. http://www.monkeyinmychair.org/
This site is targeted at parents explaining adult cancer to their children.
Short URL for this web page: http://bit.ly/TWTalk