I’ve seen a lot of different threads on the newsgroups and internally from customers asking when Service Pack 1 for Windows 7 and Windows 2008 R2 will be released. The answer is: soon. I don’t have an exact date or I would post it here. However it is not uncommon for us to wait to publish something like a Service Pack or other major update until post release to ensure that it will work properly. I think the best posting explaining this was done by one of the MVPs on the forums recently (Lawrence Garvin). He said:
“For the record -- major updates, such as service packs, Internet Explorer, etc. are rarely released to WSUS concurrent with being released to the Microsoft Download site. This is because the packaging and testing of those updates cannot be started until the product is actually released. The packaging process takes some time, more or less, depending on the complexity of the package -- one of the objectives being the verification that the standard "interactive" installation can run in a fully unattended silent mode under the supervision of the Windows Update Agent.
I wouldn't expect to see Win7/Win2008R2 Service Pack 1 in the WSUS catalog before March 29th.”
Again, I don’t have any insight into the date, but it will be out in the near future
UPDATE: This is now available: http://windowsteamblog.com/windows/b/bloggingwindows/archive/2011/03/08/windows-7-sp1-available-via-wsus.aspx