Couple of days ago Windows8italia has posted screenshots from Office 15 build 15.0.2703.1000. The build looks almost the same as Microsoft office 2010 and only couple of new features has been revealed. As other upcoming Microsoft products office 15 also has the metro UI. Here are the screenshots from this build-
(http://i51.tinypic.com/30cofw8.jpg) (http://i55.tinypic.com/2gwicxt.jpg) (http://i55.tinypic.com/53ny3c.jpg) (http://i54.tinypic.com/kbt7nq.jpg)
Recently twitter user R27 has posted this video showing the installation of Office 15 build 15.0.2703.1000.
Office 15 Build 15.0.2703.1000 Installation (http://www.youtube.com/watch?v=eUlrCZlQrfs#)