Fordham University seems to be a good place to find primary sources. Some of the links to external sites are dead, but the sources found on their site are useful.
As a Latin teacher, I really wish there were a book or resource that could give a good overview of how to teach Latin classically. It seems like my two years of teaching have been largely trial and error. I have been making progress, but it seems like there needs to be a better, faster (wow... have I bought into American thinking so much that I now want the microwave meal equivalent of experience, too?) way to learn what I need to in order to teach my students the way that I ought to. As a teacher, I know that students do not learn by being fed information. It takes seeking, digging, ingesting, and digesting information to make a real student and lover of learning. So I know that just as it won't work for me to tell my students the information they need to know, it won't work for someone else to tell me the information I need to know. Experience comes from trying, literally. (etym: Experience<experiens<experior, to try, endure Lat.)