A software application developed for use on Apple's iOS-powered iPhone devices. iPhone apps are available through the Apple App Store and are designed to run on Apple's iOS mobile operating system, which powers the iPhone as well as Apple's iPad and iPod Touch devices.
Android apps are available in the Google Play Store (formerly known as the Android Market), in the Amazon Appstore and on various Android App-focused sites, and the apps can run on Android smartphones, tablets, Google TV and other devices.
The process of getting a Windows Mobile application out to the rest of the world can appear daunting, but this section sets out the steps to follow in order to package and distribute a project. If nothing else, you should read the blog entry below that covers installing the SDK Certificates.