At vagrantbox.es, you can find boxes for many flavours like CentOS, Ubuntu, Debian etc.
How ever, you might require a flavour of OS that is not available packaged for you already.
In such a case, you might want to package it for use with Vagrant.
I needed Oracle Enterprise Linux Box.
Following is a step by step approach to create a base box for Oracle Enterprise Linux 5.7 64 bit version.
Creating a VM on VirtualBox
Step 1: Get the ISO file from which we will install the Oracle Enterprise Linux.
Step 2: Create your virtual machine on VirtualBox.
Create a new Virtual Machine Type: VMDK Name : oel57 Base memory size: 512 MB, Memory Space Maximum 40 GB Enable Host I/O cache