We've just published an update to the Windows Mobile 6 SDK Documentation to MSDN. Now, don't get too excited - this update is more of a "polish" that anything else, and we've focused on fixing up a few loose ends, improving some graphics and adding more explicit information on getting started and installing the development tools. The better stuff will be coming soon enough, don't worry 😉
Here's the handy url: http://msdn.microsoft.com/windowsmobile/docs
Just a reminder: these online docs are much more up-to-date than the standalone docs installed as part of the SDKs, and you should definitely use them when you can.
Which brings me to this key question: How important is it to you to have an up-to-date download available of the latest docs to run locally? For example, if I could wave a magic wand and say "click here for the latest docs in PDF format or as a CHM collection", would you click here? Which would you prefer?