Another good site is listed below. The name is perhaps a bit misleading because of the "millionaire" word, but put that aside while I quickly post the premise.
The idea is that by eliminating debt and following a simple long-term strategy, the money will be there when you retire because of compounded interest. The site is simple, non-technical and even has a "millionaire calculator" so that you can see how your savings will add up over a series of years given the history of the financial markets.