Well first of all, there is dispute about the jurisdiction of the USDA in terms of taking away Armstrong's titles. The ICU makes decisions on this matter, and without a failed drug test (unlike floyd landis who failed his), there is very little they are willing to do.
So according to the USDA, Armstrong cheated, but nothing has officially occurred in terms of taking away his titles. The USDA released these documents in order to wage a publicity war. They want the popular opinion to be that Armstrong is guilty, because that will help their case in dealing with the ICU.
Personally, I won't believe anything the USDA has to say because they refused to offer Armstrong a trial by jury when he specifically requested one. They themselves do not believe their evidence will hold muster in a fair trail, judged by Armstrong's peers.