Facebook is working on a Windows application that will give users access to Facebook Messenger. The application with a chat feature, ticker and notification system is still in b lwa ta and by a select group of users tested.
Facebook has already a page online in which a few questions about the new application requirements. There you can read that the application has a chat feature, the recently launched ticker and the notification system. From the screenshots that the application is probably a wrapper and that the content via html5 is built. Facebook fits that method for a while with his mobile applications.
Login is handled by the browser; who is logged on to the website of Facebook, it is immediately in the application, if it is installed. Also the privacy settings are synced between the website and the application. Not all chat options are supported; so is it not possible to play with more than one person to chat and also video calling is still not an option.
The application, which, incidentally, only on Windows 7, is currently in beta test and therefore not yet for the general public to download. Sign up for the beta is not possible. Facebook has not yet disclosed when the application for everyone should be available.