直接下载 virtualbox 包安装时，有时要安装依赖包，比较麻烦，所以用yum来安装比较方便，
步骤如下：
Install Fedora or RHEL Repo Files
cd /etc/yum.repos.d/ ## Fedora 17/16/15/14/13/12 users wget http://download.virtualbox.org/virtualbox/rpm/fedora/virtualbox.repo ## CentOS 6.2/6.1/6/5.8 and Red Hat (RHEL) 6.3/6.2/6.1/6/5.8 users wget http://download.virtualbox.org/virtualbox/rpm/rhel/virtualbox.repo
Update latest packages and check your kernel version
yum upgrade
Install VirtualBox Latest Version 4.1 (currently 4.1.18)
yum install VirtualBox-4.1