Today Microsoft has officially announced that Windows Phone 7 Team has signed off “Mango” RTM build and developers may get early bits very soon.

Earlier this morning, the Windows Phone development team officially signed off on the release to manufacturing (RTM) build of “Mango” – the latest version of the Windows Phone operating system,” Terry Myerson.

The update (Mango) will be pushed to all existing Windows Phone users free of charge and provides over 500 new features including third-party multitasking, conversation view for email, improved Office apps, a full HTML5 web browser, custom ringtones, integrated instant messaging via Facebook and Windows Live Messenger, new Bing search features, and more.

http://www.youtube.com/watch?v=OP30F3ZxTmw

The new devices powered by the Windows Phone Mango operating system may out of shelf sometime this fall.