VirtualBox Guest Additions en CentOS 6

Extraido de http://donalddenney.com/content/virtualbox-guest-additions-centos-6:

1. yum install gcc make kernel-devel-2.6.32-71.el6.i686
2. sh /media/VBOXADDITIONS_4.1.0_73009/VBoxLinuxAdditions.run
3. Reiniciar