The developer kit for Windows Mobile 6.5 (including documentation) is now up here: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=20686a1d-97a8-4f80-bc6a-ae010e085a6e. You might remember me talking about this at the Tech Ed session last month.
Also included are some samples on the new Gesture APIs. WM 6.5 also supports a new programming model called Widgets (lightweight script applications that run inside an instance of IE6). And yes, WM6.5 does come with Internet Explorer 6. Finally!