"Mango" is expected to be released in September this year, and brings 500 new features to the Windows Phone 7 platform, including Multitasking, IE9, OS-wide IM integration, deeper social networking and more.
Bill Cox, Senior Director of Communications at Microsoft for the Windows Phone Division just hours back tweeted:
According to sources, the "juicy surprise" refers to the Mango beta release, which is due to be available on the App Hub as soon as Thursday June 30. And, we're hearing that we could see the announcement (or at least Mango appearing on create.msdn.com) within the next 6-12 hours. The build number attached the the release should be 7661.WP7_5_Trial. Our sources are agreeing that Thursday is the day for the beta to hit the App Hub.
We'll update this post, if we get new information about the WP7 today, or check our blog for the latest news.