I would like to customize Holo theme by changing the default blue color to fit my company color. Is there an easy way to do this? Or I have to redefine the style of all componen
As an addition to Waza Be's answer, you might want to use this for styling the Action Bar:
The Android Action Bar Style Generator allows you to easily create a simple, attractive and seamless custom action bar style for your Android application. It will generate all necessary nine patch assets plus associated XML drawables and styles which you can copy straight into your project.
This blog has an excellent tutorial on how to use it properly.