Thought I’d try out the Autolink plugin. According to its very brief documentation, it can tell automatically link to movies by adding a [movie]…[/movie] pair.
But I can’t get it to work :-( It complains that my Google API Key isn’t valid. I’ve only just got a Google Base API key, so this is odd. I've looked at the code and see that it's using the Google SOAP Search API, which is now deprecated, and you can't get new keys for it. It’s been replaced by the Google AJAX Search API. I think (but could be wrong) that therefore any users without SOAP-valid API keys can't use this.