You must first install the Android SDK. Then, launch the graphical updater and let it install all of the packages. I think there's like 8 of them. Once done, cd into the directory it's installed in (mine was /opt/android) and then cd into the directory "tools". The emulator is in there. However, I recommend you use Eclipse as your IDE for Android. It really makes it very easy and noob proof. All you need to do is click the "Run" button. You can find details on that here.
- For getting the SDK installed and Eclipse set-up (omit eclipse part if you wish)
- For using the command line and a text editor of your choice