HHS/CMS Center for Medicaid and State Operations
CMS-provided Search Wizard for Medicaid information
http://cms.hhs.gov/medicaid/

CMS Welfare Reform and Medicaid Letters
CMS letters and guides related to both Medicaid and Welfare Reform
http://cms.hhs.gov/medicaid/welfareref/

SUPPORTING FAMILIES IN TRANSITION:
A Guide Expanding Health Coverage in the Post Welfare-Reform World
A federal guidance jointly issued by CMS and Family Assistance to address federal legal and policy issues related to expanding the availability of Medicaid while implementing welfare reform.
http://www.acf.dhhs.gov/welfare.pdf

Child Health Insurance Program
http://cms.hhs.gov/schip/