Ballmer is on a roll today, at the 2011 Japanese Microsoft Developers Forum in Tokyo, Japan, Baller announced the first details about the next major release of Windows Phone 7, Windows Phone 7.5. The upcoming release dubbed "Mango" is set to feature over 500 new features added to Windows Phone 7.

Ballmer goes on to say:

We have a big launch event to talk about the next release of Windows Phone tomorrow, so that information will be forthcoming, including some of the particulars about who is going to be building Windows Phones and which carriers are going to be offering them here in Japan.

Details of what is included in Mango are sparse, but speculation is leading toward opening up multi-tasking for all third-party apps, connectivity with their motion-based Kinect sensor and Mobile Internet Explorer 9.