By katsumii on Nov 19, 2013
There are 2 VirtualBox yum channels as the page below says.
Users of Oracle Linux 5 and 6 can use the public yum repository
Users of Oracle Linux / RHEL can add the Oracle Linux repo file to /etc/yum.repos.d/
You might wonder what the difference is. I casually browsed both directories via ftp and noticed that VirtualBox-3.2.x86_64 is still there only on the latter repo. For versios 4.0 and above, I don't find any difference in minor version numbers.