Learning resources for ZhengMa input method?
If you use Windows 7, there should be a text document within the Program Files that contains a comprehensive list of Chinese characters and their ZhengMa codes. On my computer it is found at C:\Program Files(x86)\Windows NT\TableTextService; it is called TableTextServiceSimplifiedZhengMa.txt

I don't know if this exists on other operating systems.
Hope it helps!