I wrote a simple  osdx to implement federal search for MSDN on windows 7 . you can click here file to download .

Here is the osdx code,you can modify it and save as msdnsearch.osdx

<?xml version="1.0" encoding="UTF-8"?>
<OpenSearchDescription xmlns="http://a9.com/-/spec/opensearch/1.1/"
>
  <ShortName>MSDN  Search</ShortName>
  <Description>OpenSearch for MSDN via Windows 7 Search Federation.</Description>
  <Url type="application/rss+xml" template="  http://social.msdn.microsoft.com/Search/Feed.aspx?query={searchTerms}&amp;locale=en-US&amp;format=RSS"/>
                                          
  <Url type="text/html" template="http://social.msdn.microsoft.com/Search/en-US/?query={searchTerms}"/>
<LongName>MSDN Web Search</LongName>
   <Contact>duanjunyi@live.cn</Contact>
   <Image height="16" width="16" type="image/vnd.microsoft.icon">http://blogs.msdn.com/favicon.ico</Image>
    <Developer>Duan Junyi</Developer>
   <Attribution>
     Search data Copyright 2009, Microsoft.com, Inc., All Rights Reserved
   </Attribution>
   <SyndicationRight>open</SyndicationRight>
   <AdultContent>false</AdultContent>
   <Language>en-us</Language>
   <OutputEncoding>UTF-8</OutputEncoding>
   <InputEncoding>UTF-8</InputEncoding></OpenSearchDescription>