Windows 7 SP1 download links go live for TechNet, MSDN users
As we've said before, SP1 won't bring many (if any) visible changes to the average user. In addition to rolling up previously available updates, Windows 7 SP1 introduces some key virtualization and remote desktop improvements.
Subscribers may want to wait until the initial rush subsides -- Microsoft's servers typically get slammed hard when top-tier downloads become available. Otherwise, we recommend downloading with the Akamai downloader. It's working well for us at the moment.