Few days after releasing the Service Pack 1 for Windows 7 and Windows Server 2008 R2 as RTM and made it available to download to TechNet/MSDN/Premier subscribers, Microsoft has provide public download for this Service Pack

http://www.microsoft.com/downloads/en/details.aspx?FamilyID=c3202ce6-4056-4059-8a1b-3a9b77cdfdda&displaylang=en

In the mean time, the SP1 is also available through Windows Update