We knew Windows Phone 7 was scheduled to land first internationally, but it’s always a treat to hear the particulars. Orange UK has just (re)revealed that it’ll be the exclusive carrier of HTC’s 7 Mozart across the pond, and it’ll be joined by Samsung’s Omnia 7 as both go on sale tomorrow morning in Orange’s Oxford Street shop — fittingly, at 7am local time. Naturally, the carrier is going to blow out the launch, with each customer buying a WP7 handset to receive a complimentary Bluetooth headset… while supplies last, anyway. You’ll also get a stockpile of Orange applications and services (like it or not), and we’re told that each phone will be offered for zilch with a fresh contract starting at