Microsoft has unveiled its new mobile operating system Windows Phone 7, and the ten devices which will be running it. HTC is releasing five of the devices, while LG is releasing two and Samsung and Dell are also among those releasing Windows Phone 7 handsets. "The difference with Windows Phone 7 isn't just what you're going to do with the phone, but how you're going to do it. We've focused in on the way real people want to use their phone when they're on the go. We've set out to build a phone that is thoroughly modern," Microsoft chief executive, Steve Ballmer said at a press conference in New York.