Insert the following in /etc/fstab

<code>
none /proc/bus/usb usbfs devgid=123,devmode=666 0 0
</code>

UPDATE:

To get it working on Intrepid Ibex I added this:
<code>
#Make USB Work in Sun VirtualBox
none /proc/bus/usb usbfs devgid=46,devmode=664 0 0
</code>

Execute:
<code>
sudo mount -a
</code>

Now you should be okay to run Vbox and use USB devices.