Follow the instructions given below.
1.Download Eclipse IDE
First step is to download Eclipse IDE from http://www.eclipse.org/downloads/packages/eclipse-ide-java-developers/ganymedesr2. We need this software to use as a development environment for Android.
2.Download Google Android SDK
We need to download Google Android Software Development Kit for development. Go to http://code.google.com/android/download.html, read and agree to the license and click the "continue" button. Choose the platform that you are currently running on. Once downloaded, locate the archive file and extract or expand it to a location that you will remember. Note the location, as you will need to enter this directory into Eclipse in a moment.
2.Configuring add-on in Eclipse
Start the Eclipse from installation directory.