Andy Lees, president of Microsoft's Mobile Communications Business, said the changes are designed to "make the smartphone smarter and easier. ... This lays out the focus of the Mango release, smarter and easier for communications, applications and the Internet."
Microsoft launched Windows Phone in October. Microsoft gave no update today on how many people have bought Windows Phone devices.
Microsoft did say that Nokia's first phones will run the Mango release, and Microsoft is already testing it on Nokia phones in labs in Redmond.
New handset partners Acer, Fujitsu and ZTE will make phones that run the Mango version of Windows Phone. Samsung, LG and HTC will also make new phones that run Mango. Microsoft did not say when Nokia, a new partner, will ship its first phones running Microsoft's mobile operating system.
Microsoft said there are now more than 18,000 apps for the Windows Phone.
"For the ecosystem, the stars are aligning," Lees said. "We think Windows Phone Mango will be a tipping point of opportunity."
Microsoft had some problems with its last update for Windows Phone called NoDo, and many phone owners complained that it was late and confusing when they would receive it.
Here are some areas of improvement for Windows Phone in the Mango release.
Mashing Facebook, Twitter and texts in the address book. Each contact in the address book will show a communication history, including Facebook chats, tweets and previous emails, texts and voice mails. You can group people together in the address book in lists and launch Facebook messages to the group.
Text messages can be read aloud by the phone, and the phone can convert speech into text messages.
Applications will get three-dimensional graphics. The company showed a British Airways app with a seat chooser that lets the person do a virtual walk through of the plane. The app also pushed a QR code for a boarding pass to the home page of the phone screen. Users will see these new features only if developers take advantage of them in building new apps.
Bing will be able to do visual search with the phone's camera, such as snapping a photo of a book cover and connecting the phone to a Bing search about the book. Quick cards from Bing will pull together relevant information on a restaurant or concert venue and link to relevant apps.
Internet Explorer 9 will be coming in a mobile version.
Microsoft said the update will include more than 500 new features.
Join us back here at noon Tuesday for a Seattle Times live chat about all the new features in Windows Phone.