Check out the new article posted on MSDN for some high level information about what developers can achieve with Windows Mobile 5. It is a great read, even if you are not a developer, to get a feel for what can be achieved on the devices and how simple device development is. Here's the official blurb:
Summary: Jim begins a series of articles exploring the new tools and application programming interfaces (APIs) that developers will find in Microsoft Windows Mobile 5.0, Visual Studio 2005, and the .NET Compact Framework version 2.0. The series begins with an introduction to Windows Mobile 5.0 and the tools needed to get started developing for Windows Mobile 5.0 today.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dntake/html/yctiwy_wm5.asp