The special delivery envelope is one which you get from the post office. You have to have it with you otherwise the embassy send you out for a little walk to go and get one. It is basically some sort of next day, self addressed recorded delivery service. The forms which you will have to take with you come from two sources 1. The embassy and 2. The flying school. As far as I'm aware, the type of forms which the school sends you, very much depends on which school it is. Not much help in there really I'm afraid. When speaking to the embassy on the phone, you don't get a great deal of information. I ended up simply liasing with the flight school and the embassy to try to sort out the contradictions. In the end the flight school called the embassy to sort it out because I was being told the opposite of what the school was told by the embassy. Got there in the end though!!
Hope this is some help for you.
scotte