I've been playing around with the iPhone lately and I have to say, I love it! The user interface is pretty slick and the touch screen functionality is outstanding. They just opened up their platform for developers so I predict a lot of cool applications in the future to complement this tool. Definitely a watershed moment in mobility devices. 

I wrote a quick one over the weekend with one of my calculator scripts so if you have an iphone, feel free to add this application. http://www.apple.com/webapps/calculate/mortgagecalculator_rockongroup.html. 

Mortgage Calculators