Centos recently published v6.2. 
Out of the box is Firefox 3.x and no Google Chrome installed.
Steps to install Google Chrome 16 (as root)
Steps to install Firefox 9 (as before as root).
To install the Virtual box Guest Additions:
- yum update
- yum install gcc
- yum install kernel-devel
- Mount Guest Additions iso image
- Run autostart on the cd
- Enter root password
- After install reboot vm
Tags: centos, firefox, google chrome, Linux