The Windows Automated Installation Kit (Windows AIK) for Windows 7 SP1 is available for download since yesterday.
The WAIK contains tools like ImageX, DISM, WinPE, USMT and VAMT.
This update isn’t needed to deploy Windows 7/Server 2008 R2 with SP1 or the standalone Service Pack 1, it is an optional update. Be sure to read what is changed in this version: http://technet.microsoft.com/en-us/library/dd349350(WS.10).aspx#SP1
Download WAIK for Windows 7 SP1 at Microsoft. (this is pointing to the original WAIK 2.0, not version 3.0! Read more below).
UPDATE: Apparently Microsoft didn’t updated the WAIK ISO, but only released supplemental files for the WAIK. These supplemental files are packaged in an ISO file (waik_supplement_en-us.iso), and doesn’t contain an installer like the original WAIK. You need to extract the ISO and (old school) xcopy the content to your Windows AIK directory (\Program Files\Windows AIK\Tools\PETools\).
Contents of the supplemental ISO file (waik_supplement_en-us.iso):
(X)Copy them to:
C:\Program Files\Windows AIK\Tools\PETools
More on Michael’s blog.