Exciting news!  As of this morning, Windows Mobile SDK is now included as a category for bugs/suggestions in the MSDN Product Feedback Center.  For the past several months, people have been submitting great feedback to our partner teams line .NET Compact Framework and Visual Studio for Devices.  Now, you can send stuff to us as well.   
I'm really excited about this feedback mechanism.  You get to see what others have written, add you vote to something, add repro steps or workarounds, track status, and rest assured that what you send in is actually going straight to our internal bug tracking database where it will be reviewed by the development team.
Is there an API missing from Pocket PC or Smartphone that you'd like to see?  Maybe there's an API we have which doesn't work as expected?  Or maybe there's something that works but seemed more difficult that necessary to use?  Head on over and let us know.  Just pick "Smart Devices" as the technology and then when you get to the point of adding a new bug/suggestion, pick "Windows Mobile SDK" as the category.
For now, this is only for developer-related feedback.  If you have end-user feedback, please continue to use the newsgroups or MSWish.