This blog post explains how to use the diskpart utility on the Windows 7 install DVD/USB to create a virtual drive you can mount and install Windows onto.
At next startup, you’ll see Windows 7 in the boot menu!
Is this still possible with the Windows 8 dev preview DVD? Can I do this without burning the image to a DVD using virtualization? How do I extract the virtual disk image with Windows 8 from the virtual disk image used to virtualize? If I need to hand edit my bootloader how can I do that?