Active Directory/Documentation/IE7 Feeds

The RSS store is a set of OLE documents (a two-decade old technology, which is not cross-platform), and is installed on a per account basis. If your Windows account name is <user>, then the RSS store is stored in:

C:\Documents and Settings\pgmurphy\Local Settings\Application Data\Microsoft\Feeds\FeedsStore.feedsdb-ms

http://www.arstdesign.com/articles/rssstoreviewer.html