We do not have an EndNote application for Android devices. At this time the iPad is the only mobile device for which we have an application.
If you have an EndNote Web account, you can use the browser on the Android device to log into your EndNote Web library. You can add references to your EndNote web library, and if you are using EndNote X6, you can synchronize your EndNote Web library with your EndNote Desktop library. If you are using EndNote X5 or earlier you can transfer records between the Desktop and the web in either direction.