Microsoft released Windows 7 SP1 blocker tool kit which allows to block Windows 7 SP1 update installation without disabling Windows Automatic Updates. Microsoft will automatically upgrade Windows 7 to Windows 7 SP1 through windows automatic updates once SP1 hits RTM milestone.

Windows 7 Service Pack1 blocker tool

Following the availability of Windows 7 Sp1 RTM, Windows 7 SP1 blocker tool will prevent installation of service pack 1 updates through windows update. After 12 months, Microsoft automatically upgrades Windows 7 to Windows 7 Service Pack 1 through automatic updates irrespective of  blocker tool installed in your Computer.

Windows 7 SP1 blocker tool      via [webtrickz]