For Windows 7 and Server 2008 R2 the first service pack (SP1) will be released until end of February 2011.
Download:  http://technet.microsoft.com/en-us/windows/gg635126.aspx

What’s included in Windows 7 Service Pack 1 (SP1)?

The SP1 for Windows 7 contains among others the MDOP package (Microsoft Desktop Optimization Pack) and provides with Microsoft Bitlocker Administration and Monitoring (MBAM) a better management for all security functions for BitLocker and BitLocker ToGo.
See more on here: http://windows.microsoft.com/en-US/windows7/whats-included-in-windows-7-service-pack-1-sp1 
An Excel list with all ins SP1 for Win 7 contained fixes, sortet by KB number can be downloaded here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=61924cea-83fe-46e9-96d8-027ae59ddc11&displaylang=en

The SP1 for Server 2008 R2 contains among others RemoteFX for accelerated graphic options on virtual desktop infrastructure.

All license customers as well as MSDN and TechNet abo owners can access the SP1 bits on 16th Febr. 2011. On 22th February 2011 it will be available for everybody.

Microsoft continuously collects feedback on Windows 7 and Windows Server 2008 R2 operating systems from its customers and partners. This feedback results in enhancements that help improve compatibility, reliability, performance, and user experience. These enhancements are made available as regular updates delivered via Windows Update or from the Microsoft Download Center. By integrating these updates into a thoroughly tested single service pack, Microsoft aims to provide a high-quality update that will minimize both deployment and testing complexity for customers.

Direct links and Content:

Documentation for Windows 7 and Windows Server 2008 R2 Service Pack 1 (KB976932)
Release Notes: Important Issues in this Release of Windows 7 with Service Pack 1
Learn how to install Windows 7 Service Pack 1 (SP1)

Windows Server 2008 R2 Service Pack 1 (release notes, Deployment Guide, etc.)

Related links:

RemoteFX – Rich End User Experience for Virtual and Session-Based Desktops
http://www.microsoft.com/windowsserver2008/en/us/rds-remotefx.aspx

Microsoft Desktop Optimization Pack (MDOP)
http://www.microsoft.com/windows/enterprise/products/mdop/default.aspx

RC-Version:
Windows 7 and Windows Server 2008 R2 Service Pack 1 Release Candidate (KB976932)