There is a easy way of doing this by just using easy_install (A Setuptools to package python librarie).
Assumption. Before doing this check whether you have python installed into your Centos machine (at least 2.x).
Steps to install pip.
So lets do install easy_install,
sudo yum install python-setuptools python-setuptools-devel
Now lets do pip with easy_install,
sudo easy_install pip
That's Great. Now you have pip :)