Microsoft quietly rolled out Windows 7 and Windows Server 2008 R2 Service Pack 1 Release Candidate yesterday.
The software is a one-year trial version (It expires Nov 11, 2011) and will ultimately replace the Windows 7 Service Pack 1 Beta introduced a while back and currently in use by many public testers. Installation of the new RC requires a licensed and validated copy of Windows 7 for installation.
Available in a variety of downloads, the new 'test' service pack embraces Dynamic Memory and Remote FX, rolls up many of the security and other enhancements introduced since the Beta, and generally seems targeted at businesses.
The catch? You're going to have to uninstall that very stable and just solid copy of Windows 7 SP1 Service Pack Beta (which you would have had to do at some point anyway).