If you’re using ConfigMgr 2007 SP1 and have already moved to Windows 7 and/or Windows Server 2008 R2 you’ve probably noticed that they’re not listed as supported platforms. Well that all changes today as we just released a new update that enables you to add them. This update is not required to support a client. It is required only if you want to use the "SMS Platforms" setting for the software distribution, software update management, and desired configuration management features. However, we recommend that you apply this update.
KB974013 - Update available that enables you to add Windows 7 and Windows Server 2008 R2 as supported platforms for Configuration Manager 2007 Service Pack 1
J.C. Hornbeck | Manageability Knowledge Engineer