VirtualBox WinXP host, Linux Partition guest?

[Steve Lamb <grey@dmiyu.org>]

Hello,
    Anyone know how to get VirtualBox to make a definition to book a Linux 
host from a partition?  The instructions I have found thus far reference the 
partition as /dev/sda...blah.blah.blah....  That's great for when I want to 
boot Windows from my Linux partition (might try that tonight) but I want to do 
the opposite.  :(