VBox

The installation of virtual box in ArchLinux can be done with the following command.
pacman -S virtualbox

Once installation has been done, it is necessary to load the kernel module of virtual box driver.
There are 2 ways to do that. Launch the module manually at each reboot.
modprobe vboxdrv
Or modify /etc/rc.conf by adding vboxdrv in the array MODULES for a result like this:
MODULES=(vboxdrv)