I have been saying for a while that one day (probably in 2020 ;-) Windows Mobile will be open source. I do not see any other option for Microsoft in the long term. They will have to capitulate, although I was convinced they would fight this hard.
Instead, I bumped into a few sites that recently claim that the new Danger Sidekick 2009 will run NetBSD.
As you probably know, Microsoft bought Danger. Rumors abound of Microsoft coming up with a phone very soon (MWC?). If there is one, it will come from Danger - for sure. Some even say it will have the Zune brand (yep, some think it is a good brand... I would call it actually the Zune Vista to reinforce the brand with another good one ;-)
Now, it would have made sense for Microsoft to force Danger to use Windows Mobile. Maybe they thought about it. But probably it ended up not making sense (do you want to throw away years of work and a bunch of enthusiastic users just to push Windows Mobile?). Maybe they even realized why open source is better as a model (but they are not telling anyone ;-)
Therefore, they probably got stuck with what Danger had. And that is said to be NetBDS. Which is open source. As recent as last October, Microsoft was "looking for a talented NetBSD software developer interested in helping Danger (a subsidiary of Microsoft) ship the next generation of Danger’s Sidekick platform"... It does not leave that much doubt.
If I can't have Windows Mobile open source soon, too bad. I can live without it for a few more years. But if the other mobile OS from Microsoft is open source - the consumer one - I would be moving an inch closer to my prediction...
Open source for consumers, closed source for enterprises. Interesting choice. Sooner or later, it will be open source everywhere. That is where the world is going, after all. Microsoft is just going with the flow.