All kinds of financial calculators covering everything from simple interest loans to retirement projections.
Alliance for Investor education
Dedicated to facilitating greater understanding of investing, investments and the financial markets. They pursue initiatives for education and join with others to motivate Americans to obtain objective information and increase their knowledge and understanding of investing.
U.S. Treasury site on savings bonds. You can even buy these bonds online.
Dimensional Fund Advisors
A no load nationally reputed mutual fund company that works with some of the world's leading financial economists including a Nobel Prize winner to develop and enhance their strategies. These funds can only be purchased through a select group of fee only financial advisors.