It is not the first time Windows Phone 7 has been demoed to the public. However, I must give credit to this video which shows a real working prototype (not simulator) that appears fast and smooth. BTW, it is a Samsung phone. And also, it shows the Bing integration with Voice Search function. Video after the break.
I particularly like the album and camera function. It seems that Microsoft has scored well so far in terms of UI. However, I have to say again that the main menu is a let down. The success of this new OS will depends on the stability and the developers that will develop apps for it. Without apps, this phone may only serve well for the corporate or enterprise users (IMHO).
Here is the video.