As you know that Microsoft had launched Windows 7 SP1 Beta to public and if you wanna download thr final/RTM version of SP1 then you have to wait a bit.Because according to Microsoft the SP1 of Windows 7 will be made public in the first half of 2011.
According to Brandon LeBlanc @ WindowTeamBlog :-
Windows 7, SP1 is simply a combination of updates already available through Windows Update and additional hotfixes based on feedback by our customers and partners.
If you are an IT Professional interested in testing Windows 7 SP1, you can download the public beta via the Springboard Series on TechNet where you will find the download as well as other key deployment and support tools. For everyone else, Windows 7 SP1 will be available in the first half of 2011 through the usual channels.
