Web Site Enhancement - mortgage calculator

I'm working on several exciting improvements to my web site, and this is the first.  It's been a long time coming, as many of you have asked if there is any way to integrate an easy to use mortgage calculator along side the property listings.  At last, the calculator is in place --- allowing you to quickly determine the principle and interest of your monthly mortgage payment. 

Enjoy, and let me know if you have any difficulties using it.