Calculate is a free app from QxMD. It is a decision support tool that has over 150 clinical calculators. It is available for the iPhone, iPod Touch, BlackBerry, and Android.
The app is an upgrade and integration of the other QxMD's apps for Cardio Calc, Neph Calc, GI Calc, Heme Calc and Pregnancy Wheel.
User feedback is very high for this app. Check it out for yourself!
Watch this non-narrated quick tour: