How can I accurately calculate a mortgage payment?

I roughly calculated that 5,000 divided by 360 months would be 7.23 per month BEFORE interest, insurance, etc. I used an online mortgage calculator and was informed my monthly payment was over 4 per month! How is that possible even when including the 6% fixed interest rate, insurance, etc? When I search real estate websites, [...] http://bit.ly/lZQXcL