Visual Studio RTM is finally available to MSDN subscribers and TechNet since a few weeks now.
You can see the compatibility and system requirements for Visual Studio 2012 here : http://www.microsoft.com/visualstudio/11/en-us/products/compatibility
I can actually tell you that it's not compatible with Windows 8 RC. So if you want to run it on Windows 8, you might want to download if from your MSDN Subscription or you can download the trial version of Windows 8 Enterprise which is available here : http://msdn.microsoft.com
It offers you a 90 days trail.