Microsoft announced a scaled down version of Visual Studio 2008 called the Visual Studio Shell. The Visual Studio Shell, which will be in beta sometime this summer, is designed to allow developers to bundle Visual Studio functionality into their own products and will integrate languages such as Fortran, Cobol, Ruby, and PHP. The Visual Studio Shell will be free and will ship with Visual Studio 2008.
There are two different “modes” that can be used when integrating Visual Studio Shell: integrated and isolated. The integrated mode is built upon the existing Visual Studio Premier Partner Edition 2005 while the isolated mode allows partners and developers to build products on top of Visual Studio (integrating their product directly into Visual Studio) including the ability to customize the application so it doesn’t necessarily look like Visual Studio.