Windows 7 is the next release of the Windows client operating system, built on the secure foundation of Windows Vista and Windows Server 2008. Performance, reliability, security, and compatibility are core tenets of this release as we collect your feedback to meet our engineering goals of making Windows 7 the best-performing and most stable Windows operating system to date. New innovations in the product are designed to augment your ability as an IT professional to better provision and manage increasingly mobile PCs, protect data, and improve both end-user and personal productivity.
Windows 7 RC (Scroll down page. Select language and version)
Windows 7 homepage