Action bar on devices before API 3.0

The action bar has been introduced in Android 3.0. If you want to use the action bar on devices with an earlier Android release, you have two popular options.

First, you can use the Open Source project called ActionBar Sherlock which allows you to use the action bar on Android devices as of Android 1.6. You find this library under the following link.

http://actionbarsherlock.com 

The second option is to use the ActionBarCompat library from the Android support library v7, which supports the action bar as of Android 2.1. See the following link to setup the support library v7 in your project: Setting up the support library.

참조 : Using the Android action bar (ActionBar) - Tutorial (Good Article)
http://www.vogella.com/tutorials/AndroidActionBar/article.html

추가) 2014.11.26

Add ActionBar to Android 2.x (v7 appcompat library)
http://hmkcode.com/add-actionbar-to-android-2-3-x/