Searching the web for spanish documentation about creating classes for LaTeX, I found this website belongs to the class of "Scientific text processing in high quality" (Procesamiento de textos científicos en alta calidad) at the University of Valladolid, Spain. Specifically the PDF file apuntes8.pdf contains information about LaTeX programming techniques. Also, the other documents contains very good information about basic and advanced use of LaTeX for text processing.
I thought that is a good idea post this information here. :)
If you know another source of spanish information for creating LaTeX classes feel free to share!.