This popular tool can be used to prototype complete NDS projects without writing a single line of code.
The author of NDS Snoop has made numerous bug fixes to the original, and here's the new and improved version. For details, see this article.
NDS Snoop includes a README file with a detailed description of this tools and its components.
It now supports auxiliary classes, viewing data in hex and string format as well as selecting between multiple trees. The Readme file included with the original NDSSnoop is still accurate.
Disclaimer: As with everything else at Cool Solutions, this content is definitely not supported by Novell (so don't even think of calling Support if you try something and it blows up).
It was contributed by a community member and is published "as is." It seems to have worked for at least one person, and might work for you. But please be sure to test, test, test before you do anything drastic with it.