The Microsoft presentations at GDC 2013 are freely available from the GDC Vault.
WindowsConquering the Galaxy with Phones and Tablets: Galactic Reign PostmortemSecrets of Success for Publishing Games in the Windows StoreOptimizing for Power Efficient GPUs in DirectX/C++ Windows Store GamesCore Technologies for Windows 8 GamesDeveloping a Windows Store Game with DirectX and C++Designing Games for Windows 8 Tablets and PCs
Windows phoneIntro to DirectX C++ Game Development on Windows Phone 8Building DirectX Games for Windows and Windows Phone Building Connected Game Experiences on Windows PhoneUsing In-Application Purchase for Windows Phone GamesMiddleware Offerings for Windows and Windows PhoneFrom Our Partners: What Makes a Great Windows Phone Game
XboxDeveloping a Second Screen Experience with Xbox SmartGlass
Note: There were a number of DirectX 11 related presentations from AMD, NVIDIA, and Intel as well.