As has been said, their are no apps for insulin calculations. But their are apps to help with carb counting and blood glucose diaries. I own an IPhone and have recently indulged myself and bought an iBG star glucose machine which uses an app Ava for free from the app store. Ok the meter cost £40, but it is very small and you don't need an IPhone to use it, it works as a stand alone meter as well, but the app for it is very good and when you get your phone, you just open the app, plug the meter in and test it then sores the result with day time pre or post meal and carb count and dose.