How do I use eclipse to compile?

First install Oracle’s (formerly Sun’s) Java JDK and the Java Runtime Environment, then install Eclipse. Then make sure the Android SDK is installed and updated.

UPDATE: Google now provides their Android SDK and the Eclipse IDE in a single preconfigured download. At the time of writing this it can be found at http://developer.android.com/sdk/index.html

This is where you can start to learn to use the tool http://developer.android.com/training/basics/firstapp/index.html

The necroscope says "google search and youtube is your friend when you want to learn eclipse"