The Children's Defense Fund has a section focusing on children's health, including the Childrens Health Insurance Program (CHIPs) in each State. This site has some great links.
Health Care Financing Administration (HCFA) provides iInformation on Federal health coverage protection provided by the Health Insurance Portability and Accountability Act of 1996 (HIPAA). This site also answers questions about pre-existing conditions, special enrollment, certificates of creditable coverage, and how to cope with the denial or loss of health coverage.