Get it here http://msdn2.microsoft.com/en-us/vstudio/aa700831.aspx.
We encourage you to download and try these early releases. Before installing a release, review the prerequisites as some releases may require additional software prior to installation. As with all prerelease software, we encourage you only to install these on a secondary machine, or in a virtual machine, as they are not supported by Microsoft Services support teams. As the goal of these previews is to gather feedback from the developer community, please use Microsoft Connect to report any issues, or to suggest improvements.