Windows 7 SP1 and Windows Server 2008 R2 SP1 become generally available for download yesterday. Microsoft had previously made SP1 available to MSDN and TechNet users (as well as Volume License customers) on February 16th. SP1 is available from the Microsoft Download Center or via Windows Update. You can update your PC / Server using Windows Update. In order to save bandwidth (if you have multiple clients or servers) download the stand-alone installer.