With the recent slaying of its KIN devices, Microsoft will be looking for some good news when it comes to mobile devices, and now we might have a little hint that its Windows Phone 7 phones might be arriving a little sooner than expected. A leaked picture showing the AT&T retail signage that will be sent out for a July 24th store overhaul has surfaced, and if you look closely, you’ll notice that it lists Windows Phone 7. Granted, there isn’t any concrete information from this leak as to when the Windows Phone 7 devices will be arriving, but we do hope that AT&T is planning to announce those devices not too long after these promotional materials go live.