Previously Microsoft promised that Service Pack 1 for Windows 7 and Windows Server 2008 R2 will be available by Q3 of 2011. But rumours are coming that RTM build of Windows 7 SP1 has been signed off and will be made available to MSDN and TechNet subscribers on February 16th, followed by general public release on February 22nd, 2011.
Microsoft confirms officially at Windows Team Blog:
We officially handed off the final release (RTM) of Windows 7 and Windows Server 2008 R2 Service Pack 1 (SP1) to our OEM partners. On February 16th Windows 7 and Windows Server 2008 R2 SP1 will be available for MSDN and TechNet Subscribers as well as Volume License customers. On February 22nd, Windows 7 and Windows Server 2008 R2 SP1 will become generally available for folks to download via the Microsoft Download Center and available on Windows Update.
Sources say, the RTM build string is 7601.17514.101119-1850 that clearly states the build was compiled last year (November 19, 2010). And the same build was leaked over the web when a blog post on Russian Microsoft TechNet confirmed Windows 7 SP1 RTM is ready.
It is advised to avoid such leaked builds, because it may contain harmful viruses and can compromise your PC security.