Cnet has a runthrough of the first official Facebook app for Windows Mobile—developed by Microsoft with Facebook—whose defining feature might be that it makes no real attempt to mimic the look and feel of Facebook.
But its "address book" is way more useful than the iPhone app's, since it supplies you more instant connections to Facebook contacts via text, email or phone. The icons are nice and shiny, but otherwise it looks like it was beaten by Redmond's mobile ugly stick into the appropriate size for Windows Mobile. Like those fonts! They make my eyes wriggly with icky. [Cnet]