Joe Belfiore has taken the stage at MIX for his keynote on Windows Phone. I will update this post with news and info on future updates for Windows Phone as they occur.
Increased developer API access
Angry Birds coming May 25th
Mango will include Podcast capabilities [EDIT: As Sean corrrectly pointed out in the comments, Windows Phone already has the ability to store and play podcasts. What Mango hopes to bring is the ability to subscribe, search and download podcast while on the phone, straight from the Zune marketplace]
App search is now much better with pivot controls
App Listing now includes search and jump lists
IE9 with much better features, and new UI
Browser speed contest: iPhone4 vs. Windows Phone vs. Android…Windows Phone wins!
Announcements for custom ringtones, increased sensor support for developers, in-app pin support, Motion Sensor, Live Agents and much more.