The January CTP of Visual Studio code name "Orcas" is available for download as a self-extracting install, or installed in a Virtual PC image. You can find links to both downloads, and to other "Orcas" CTP software on the Visual Studio Code Name "Orcas" Related CTP Downloads page.
The next version of Visual Studio, Visual Studio code name “Orcas”, will provide an industry-leading developer experience for Windows Vista, the 2007 Microsoft Office system, and the Web. In addition, it will continue in the Microsoft tradition of development language innovation. To enable early feedback, this page provides links to Community Technology Preview (CTP) releases of Visual Studio code name “Orcas”, and for technologies that we plan to include in it. As previews of additional technologies become available, we will make them available from this page.
Source: "Orcas" Related CTP Downloads