Wednesday 14th Sept, during the keynote with Satya Nadella, Scott Guthrie, Jason Zander, Visual Studio 11 Developer Preview and .NET 4.5 were announced.
ASP.NET 4.5 Developer Preview includes new core functionality like WebSockets, anti-XSS encoding, granular request validation. It also includes Web Forms improvements like model binding, support for HTML5 and unobtrusive JavaScript. And there are many performance improvements in ASP.NET which when combined with Windows 8 Server can decrease startup time by 30% and reduce the memory footprint by 30%.
You can read more about all the new features that are enabled in this release by reading the What's new in ASP.NET 4.5 and Visual Studio Web Developer whitepaper at http://www.asp.net/vnext/whats-new.
You can download them from here:
Another link where you can start learning and developing your application with Visual Studio 11 Framework 4.5 is http://msdn.microsoft.com/en-us/vstudio/hh127353.