Microsoft has thrown the doors open to developers interested in working on the upcoming Windows Phone 7 Series platform, announcing new developer tools and offering the deepest look yet at the Silverlight-based architecture during keynote sessions Monday at the Mix10 conference in Las Vegas. The new tools include updates to Microsoft Visual Studio 2010 Express, Expression Blend and XNA Game Studio. Microsoft also announced an emulator running as a virtual machine identical to the phone’s OS, as well as an update to Silverlight itself.