IGoEnchi is an open-source IGS (Internet Go Server) graphical client and SGF editor for Windows Mobile. It requires .NET Compact Framework 2.0 to be installed on the device. It's licensed under zlib/libpng license. You can get more information on the project at SourceForge project page.
Download the latest release, install it to your device and execute.
Select File->IGS->Connect in the menu bar. Enter your username/password in the dialog and tap "OK". When the connection is established, go to the File->IGS again and select the appropriate action.
Runs on .NET Compact Framework 1.0