The final version of the textbook Diffeology has been validated the 5 august 2012. It began to be distributed the April 22, 2013, by the AMS in the series Mathematical Surveys and Monographs. According to an agreement with the AMS, the manuscript is no more available for download. But I put below some excerpts. Now, if you are a student and want a copy of the manuscript for your private use: send me an email and I’ may help you. 
You can also visit the Blog on Diffeology, for new exercises, remarks, and the errata file.
Diffeology, the AMS Print
September 1, 2005 — Manuscript sent to AMS,  August 5, 2012.
What is diffeology ? Get the 
Errata file here... Excerpts for Download Why this book ? Table of Contents Preface Symplectic Diffeology (Chapter 9) Afterword