TheMovieDb.org API key for MyMovies (created from my personal account -- Charlie):
e83a393a2cd8bf5a978ee1909e32d531

Authd user session key required for any writable API call, but for read, no auth needed.
http://api.themoviedb.org/2.1/methods/Auth.getSession

Movie search:
http://api.themoviedb.org/2.1/Movie.search/en/xml/e83a393a2cd8bf5a978ee1909e32d531/Transformers