Windows Mobile 7 OS = Zune HD OS?

I just found a link to a video showing what the Windows 7 OS for the smartphones looks like:

You’ll notice that it looks remarkably like the Zune HD operating system, and completely unlike the old-and-dated Microsoft Windows Mobile OS. A huge leap for Microsoft in dumping their tired Windows OS. So all the rumors over the past several months about a Microsoft “Pink” smartphone, Zune Phone, etc. may have culminated to the Windows Mobile 7 OS.

The bad think, is that all the hundreds of thousands of Pocket PC and Windows Mobile Apps in existence will probably not run under this new WM7 OS (I’m about 95% sure of that). The OS is so different, I can’t imagine the old popup menus, titlebar, dialogboxes, etc. working under WM7. So the question is: How difficult will it be to write apps for WM7 smartphones? What will the programming language be, and what does the API look like?

If I had to guess, I would say that WM7 apps will be written in some kind of .NET language, or possibly Java. Hopefully, Microsoft has thought ahead and have made it easy to create apps. It will be interesting to see the progression of WM7 over the next several months. The video states WM7 will be available on the “Holidays 2010”, which is pretty vague.