Somehow many software vendors seem to make it a sport to make it hard to get download URLs.
So here is a bunch of direct download URLs for the (almost new <g>) Visual Studio 2012 RC (formerly and internally known as Visual Studio 11).
There are both ISO files (big, but convenient for offline installation).
Web installers (depending on the choose install options, the total download can be a lot less than the complete ISO, but your system needs to be online during the full installation process).
You can find similar Windows 8 Release Preview download links here (they were distilled from the official download page, which now gives a 404 because of the atdmt link redirect is broken).
I use the x64 and x86 shortcuts for the x64 and x86 ISO links.
The Windows 8 Release Preview Upgrade Assistant also comes in handy.
The above links give a sustained transfer rate here of at least 3 megabit/second.
–jeroen