Using Hardware Devices
When building a mobile application, it's important that you always test your application on a real device before releasing it to users. This page describes how to set up your development environment and Android-powered device for testing and debugging on the device. You can use any Android-powered device as an environment for running, debugging, and testing your applications. The tools included in the SDK make it easy to install and run your application on the device each time you compile. You can install your application on the device directly from Eclipse or from the command line with ADB. If you don't yet have a device, check with the service providers in your area to determine which Android-powered devices are available. If you want a SIM-unlocked phone, then you might consider a Nexus phone. Note: When developing on a device, keep in mind that you should still use the Android emulator to test your application on configurations that are not equivalent to those of your real device.
Related: Android Development