Visual Studio 2012 and Blend for Visual Studio are our new development IDEs for Windows 8 Store applicaitons. You can get "Blend for Visual Studio" with VS Studio 2012 installation as built-in.

There are couple of new versions of Visual Studio, If you want to develop Windows 8 Store applications only,  you can use Visual Studio 2012 Express for Windows 8.

You can download Visual Studio Express 2012 RC for Windows 8 from here and Visual Studio Ultimate 2012 RC for Windows 8 including desktop application development from here in the coming days for new tools from visual studio site.