Here is a list of all windows phone sessions from MIX this year, (list taken from AppHub)
Day 2 Keynote
Joe Belfiore
Application Design for Windows Phone
Megan Donahue
XNA Game Studio for Fun, Profit, Danger, Excitement and Windows Phone 7 Games
Rob Miles
Expert Lessons: Top Tips to Building a Successful Windows Phone Application
Stefan Wick
Who Would Pay For That Feature? Adding Analytics to Your Windows Phone 7 Applications
David Poeschl
Rx: A Library for Managing Asynchronous Data and Events in Your Windows Phone 7 Application
Jim Wooley
What’s Coming Next to the Windows Phone Application Platform
Andrew Clinick
Building Windows Phone 7 Applications with the Windows Azure Platform
Wade Wegner
Going Mobile with Your Site on Internet Explorer 9 and Windows Phone 7
Joe Marini
Get Ready for Fast Application Switching in Windows Phone
Adina Trufinescu
What’s New in the Windows Phone Developer Tools?
Vibhor Agarwal
Multitasking in the Next Version of Windows Phone, Part I
Darin Miller
Multitasking in the Next Version of Windows Phone, Part II: Using Background Agents
Peter Torr
Flickr API: Tap Into Billions of Photos for Windows Phone 7
Markus Spiering
Sensor and Camera Access in the Next Version of Windows Phone
Mark Paley
What’s New for Windows Phone Development with Silverlight?
Shawn Oster
Windows Phone Architecture – Deep Dive
Istvan Cseri
Analyzing and Improving Windows Phone Application Performance
Jeff Wilcox
What’s New for Windows Phone Development with the XNA Framework?
Brian Hudson
Making Money with Your Application on Windows Phone
Todd Brix
Enhanced Push Notifications & Live Tiles for Windows Phone
Thomas Fenne
Creating Windows Phone Applications Using Expression Blend
Unni Ravindranathan
New Data Access Features Coming to Windows Phone
Sean McKenna
All Thumbs: Redesigning an Existing UI to Suit Windows Phone 7
Ward Bell
The Tale of Two Apps: Making a Splash in the Windows Phone Marketplace
András Velvárt, Bálint Orosz
Over 1500 new API’s have been added to the next version of Windows Phone, called Mango. And yes, all existing devices will be updated to Mango, the update can’t come soon enough :)