Microsoft released a patch that allows Win7 SP1 and W2K8 R2 SP1 to become valid recognised clients in ConfigMgr.

As a patch, you request and download it, then apply to your Site servers and not to your Site systems. It modifies the entries in the Requirements tab of a Program so that these two platforms are included in the list of platforms available.

These two new platforms will now show up when using the following features: Software Distribution, Software Updates and Desired Configuration Management

Read the complete post at http://wmug.co.uk/blogs/r0b/archive/2011/03/29/configmgr-sp2-support-for-win7-sp1-and-w2k8-r2-sp1-platforms.aspx