Microsoft announced beta versions of Visual Studio 11 and .NET Framework 4.5.
Compatibility with previous releases
.NET 4.5 is an in-place update of .NET 4 and provides very high app compatibility for all .NET 4 scenarios
You can install and use Visual Studio 11 Beta alongside Visual Studio 2010
Visual Studio 11 Team Foundation Server Beta requires 64-bit versions of server operating systems when installing on Windows Server (see Visual Studio 11 Team Foundation Server Beta system requirements)
Features
Metro Style App Project Templates
Metro style simulator
Remote debugging
Profiling
Reduced toolbar commands
Simplified graphics
Comprehensive search
Workflow hubs
Preview Tabs
Download the Beta versions from here
Read more - New Features for Web Development in Visual Studio 11 Beta, What's New in Visual Studio 11 Beta