Microsoft's mobile efforts may look like they're slightly in disarray after the expensive and embarrassing Kin debacle, but it looks like Windows Phone 7 may yet emerge unscathed from the chaos -- and potentially even earlier than expected, if this sheet of AT&T retail signage that's being sent out for a July 24th store overhaul is to be believed. Don't get too excited, however: we're told that cards like this have hit in July for Septem