Here’s a quick tutorial that shows you how to dual boot Ubuntu 12.10 and Windows 8. Dual-Boot Windows 8 and Ubuntu 12.10
Before you begin make sure to complete the first 3 items.
1. To get started, logon to Windows 8 and right-click ‘Computer’ and select ‘Manage’.
2. Next, select ‘Disk Management’ and right-click the local disk (C:) then click ‘Shrink Volume’
3. Here, you can adjust the default value to your needs at least 5 Gigs or Higher. When ready click ‘Shrink’
4. After shrinking the drive, restart your computer while the Ubuntu CD/DVD is in the CD ROM.
5. When prompted, boot from the CD/DVD press the enter Key in your keyboard.
5. Click install Ubuntu. Next, choose (Something else) and click ‘Continue’
6. Then highlight the free space and click ‘Add’ to create a swap space.
7. Next, specify the swap amount to create. 500 to 1000 MB is a fair amount. Don’t forget to choose swap area. Click Ok to close the window.
8. Next, click ‘Add’ again to create Ubuntu partition and accept all the free space available. Make sure to select the slash ( / ) as the mount point.
9. Next, choose the filesystem ext4 to install Ubuntu on and click ‘Install Now’
10. Follow the wizard until you’re done. When you’re done, restart and boot from either Ubuntu or Windows.