As much as I hate to link to betanews articles, here it goes.
Contrary to reports which said they were released in January Microsoft today announced that Windows 7 SP1 and Windows Server 2008 R2 SP1 were released to OEM partners today, and the updates will be available to consumers on February 22.Source
As we've known since back in June when the first beta invites went out for SP1, this is a very minor release. However, the RemoteFX and Dynamic Memory virtualization features in Windows Server are especially noteworthy this time around.
With the release of SP1 today, Microsoft devoted some time to talking about a pair of new features that Windows 7 users can look forward to in the near future: Windows Thin PC (WinTPC) and Microsoft BitLocker Administration and Monitoring (MBAM.)
Windows Thin PC is a smaller, stripped-down version of Windows 7 especially designed for repurposing old PCs and feature-strapped devices into Windows 7 thin clients. This will not require a VDA license that normal thin clients do to access virtual desktops, and it will be available some time within the first quarter of this year.