Setting up a small MPI Cluster using MPICH on Linux (Ubuntu 12.04)

In the next few posts I am going to explain my experience on how to setup a MPI cluster with 3 Linux machines. I referred several online resources, extracted information and arranged them in the posts. 

Specifications:
OS : Ubuntu 12.04 desktop or server Version
MPI : MPICH2
SSH : OpenSSH
Compiler : gcc 4.6.3
NFS

This post comes in 4 parts which describes the 4  main steps and they are as follows.

1. Set up Network File System(NFS)
2. Set up SSH password-less log in
3. Install Compilers
4. Install MPICH

So let's start!
(I'm putting the list of the references at the end of the post and I thank their authors for the great work)