Mortgage Calculator

Mortgage calculator, which includes mortgage deduction?
I'm looking for a decent mortgage calculator, which factors in mortgage deduction. Basically my goal is to be able to predict my monthly payment as exactly as possible. Thanks!
Look at the calculated industries qualifier property market 2 on this site. http://www.calculated.com/12/prd150/Mortgage+PaymentCalc+-+Compact+Desktop.html It has the features you are looking for is cheap and is very easy to use.