The Microsoft presentations at GDC 2013 are freely available from the GDC Vault.

Conquering the Galaxy with Phones and Tablets: Galactic Reign Postmortem
Secrets of Success for Publishing Games in the Windows Store
Optimizing for Power Efficient GPUs in DirectX/C++ Windows Store Games
Core Technologies for Windows 8 Games
Developing a Windows Store Game with DirectX and C++
Designing Games for Windows 8 Tablets and PCs

Windows phone
Intro to DirectX C++ Game Development on Windows Phone 8
Building DirectX Games for Windows and Windows Phone
Building Connected Game Experiences on Windows Phone
Using In-Application Purchase for Windows Phone Games
Middleware Offerings for Windows and Windows Phone
From Our Partners: What Makes a Great Windows Phone Game

Developing a Second Screen Experience with Xbox SmartGlass

Note: There were a number of DirectX 11 related presentations from AMD, NVIDIA, and Intel as well.