Social Security
http://www.ssa.gov/retire2

AARP
http://www.aarp.org/money/financial_planning

The Motley Fool
http://www.fool.com/retirement.htm?ref=G02A04

Forbes Retirement
http://www.forbes.com/finance/retirementcollege

About Retirement Planning
http://retireplan.about.com/About_Retirement_Planning.htm

CNN Retirement Planner
http://cgi.money.cnn.com/tools/retirementplanner/retirementplanner.jsp