The Windows 8 Consumer Preview ISO can be download HERE
The Windows Server "8" Beta ISO can be download HERE
How to install Windows 8 Consumer Preview from an ISO image
The easiest way to convert an ISO file to a DVD in Windows 7 is to use Windows Disc Image Burner. On a PC running Windows XP or Windows Vista, a third-party program is required to convert an ISO file into installable media—and DVD burning software often includes this capability. One option is the USB/DVD download tool provided by the Microsoft Store. You can also download Windows 8 Consumer Preview Setup, which includes tools that allow you to create a DVD or USB flash drive from an ISO file (Windows Vista or Windows 7 required).
More blogposts available for Windows 8 also: