Roger Zander's SMS2003 Client tools utility called "SMS Client Spy" now has english documentation.
Myself and Sherry Kissinger put some time in to translating, so as to help describe the tools powerful features, and clarify some of the more obscure.
If you haven't looked at this tool, then follow this link to install it from the web, or here to download the binary. The tool is laid out quite well, and packed with features covering the SMS2003 Clients features.
Some of the things it can do:
It offers so much more, it's definately worth checking out!
I think Roger is about to change the tools name, so that it does not collide with the SMS ToolKit 2 utility CliSpy.exe.