Via Engagdet: "The phone operating system does away with pretty much every scrap of previous mobile efforts from Microsoft, from the look and feel down to the underlying code—everything is brand new." Video:

Microsoft has officially unveiled its new mobile OS and wiped its slate entirely clean of the oft derided Windows Mobile platform. New code, new name, and a new experience that builds on that of the Zune. It's great to see Microsoft really do its own thing here and by the looks of it do it well. Looks like we may have three viable smartphone OSes now.

Microsoft's new UI makes the iPhone's actually look out-of-date and it's fantastic to see so much courage and innovation from them. I would actually be more excited about a tablet with this OS than the iPad. The official video:

Check out the official site, too.

UPDATE:

Interestingly it looks as there will be no Flash support in this release. Considering that Microsoft has a direct competitor to Flash in Silverlight this does make some sense. Adobe's announcement of AIR for smartphone platforms somewhat undermines another attempt at killing off the platform, however.