In the future for people who want to form a new partition to dual boot windows 7 and windows 8, simply go into computer management, drive management, right click your windows 7 drive and chose shrink volume.
It will ask you to assign a size and drive letter to your new partition.
if your bios is not all ready set to boot from disk drive first then restart computer and go into bios and specify disk drive as your first boot device.
open your disk drive, insert windows 8 disk and restart your computer, windows 8 install screen will spin up, choose your freshly made partition as point to install windows 8 on to and your done.
to instal windows 8 one is going to need a install key (available everywhere, these install keys are not exclusive to individual copies of windows but rather to your windows 8 type, ie, enterprise, pro editions and what not). Towards the beginning of the install it you ask you for the install key.
Legal activation isn't possible right now, that will occur on October 26th when the retail version of Windows 8 goes on sale.