(Updated 28. april 2010: see bottom)
If you need to print, show, generate or analyse DataMatrix Barcodes on a Windows Mobile device, you can now use this class library. I have ported the code to be compatible with Compact Framework 2.0 and Visual Studio 2005.
The original full .NET framework source code is located at SourceForge.
Here is first a screenshot of the test application running on a Windows Mobile device using the DataMatrixNetCF class: