Windows 7 SP1 Changes
Microsoft Windows 7 Service Pack 1 (SP1) is available for download since past few months now, the free SP1 update to Windows 7 was pushed as KB976932 via Windows Update publicly in February this year. Microsoft has now made available official direct download links to bootable Windows 7 SP1 integrated disc images in standard .iso format, these new SP1 slipstreamed images has the added advantage that users will have an up-to-date installation just after the initial setup.
These direct download links are from Microsoft's official mirror provided by Digital River and allows users with the usual 30 days of evaluation time after which they need to activate using a legitimate key. These .iso files can be burnt as bootable DVD discs or bootable usb sticks as demoed here - http://www.megaleecher.net/Installing_Windows_Using_USB_Flash_Drive .