Windows 7 Service Pack 1 (KB976932) was released publicly in February earlier this year via Automatic updates and Standalone SP1 Installer for both 32-bit & 64-bit edition. The official download links for Windows 7 RTM DVD ISO images are across the web since long and now the Official Windows 7 ISO with SP1 Integrated can now be downloaded directly from Digital River, which is Microsoft’s online distribution partner.
Just download the desired Official Windows 7 SP1 Bootable ISO image and burn to a DVD. Next time you perform a clean installation of Windows 7 on your system, you don’t need to download and install SP1 as it’s already integrated with Windows 7. You can download all major editions of Windows 7 in English (USA) – 
 Home Premium, Professional, Ultimate. They are available for x86 and x64 systems.
New (English): 
 Windows 7 Home Premium x86 SP1 - X17-58996.iso (new, bootable)
Windows 7 Home Premium x64 SP1 - X17-58997.iso (new, bootable)
Windows 7 Professional x86 SP1 - X17-59183.iso (new, bootable)
Windows 7 Professional x64 SP1 - X17-59186.iso (new, bootable)
Windows 7 Ultimate x86 SP1 - X17-59463.iso (new, bootable)
Windows 7 Ultimate x64 SP1 - X17-59465.iso (new, bootable)

Old (English):
Windows 7 Home Premium x86 SP1 – X17-24208.iso (bootable)
Windows 7 Home Premium x64 SP1 – X17-24209.iso (bootable)
Windows 7 Professional x86 SP1 – X17-24280.iso (bootable)
Windows 7 Professional x64 SP1 – X17-24281.iso (bootable)
Windows 7 Ultimate x86 SP1 – X17-24394.iso (bootable)
Windows 7 Ultimate x64 SP1 – X17-24395.iso (bootable)
    These are NOT illegal – These are just the download links for Windows 7 SP1 ISO which is a retail package that offers a 30-day trial period. You need to activate your Windows afterwards with a genuine license activation key to continue using it. Downloading these files from Digital River is absolutely legal and completely free of charge.