Above is a good and simple loan calculator.
Here is a car loan calculator with some fancy graphs.
Here is a great student loan calculator that anyone should look at before signing off on that $25,000 student loan.
The above is an easy to use mortgage loan calculator with some graphs and charts.
How to Take Advantage of These Loan Calculator, From Around the Blogsphere
Christian PF has some good info here about the ways that one can reduce the total amount that you end up paying on your mortgage. They do this by using some of these loan calculators to help figure out just how much can be saved by a decrease in the interest rate or in the payment period.