Media Center Master
A free metadata and media organization solution for Windows.
Media Center Master maintains a free and also premium set of features that allow you to manage and automate the collection and organization of your digital media library, including a wide range of features from movie and T.V. downloads (torrents and usenet) to the acquisition of artwork, clear art, theatrical trailers, subtitles, and more. Media Center Master makes use of several unique features such as its own, private usenet news indexer and a centralized database of video file hashes to make detection of movies and videos (even with odd naming) much easier.
The program includes extended support specifically for XBMC through the use of the JSON-RPC protocol. This XBMC Integration can be configured to trigger automatic scans for new media (update the library) after each metadata fetch or be set for manual triggers when wished for by the user as well as show notifications when new media is added to your library.
User-contributed tutorial (older version):