1) # sudo gedit /etc/fstab
at the end of the file add this line:
none /proc/bus/usb usbfs devgid=46,devmode=664 0 0
(46 is the standard ID group for plugdev in ubuntu 9.04)
2) save the file
3) # sudo mount -a
That is it!
Now you can start your virtualbox with all your usb devices.
