Want to get the latest version of Windows 8 right now? This one is called the Release Preview, and it’s available for download right now. There’s a lot of little bugs resolved, the multi-monitor support has improved, and you should download it now.
You can grab the regular installer, or you can get the ISO image and use it in a virtual machine.
If you want a quick way to install it without messing up your partitions, you can read our guide on seamlessly dual-booting Windows 7 and Windows 8 the easy way, which uses the VHD boot feature to install with a virtual hard drive.