One of the benefits of an educational Ning is the 'word of mouth' they provide. Many times this has saved me trawling through potential new resources and directing me to what I am after. Two resources I wish I had come across sooner are detailed below. I hope others find them helpful in teaching documentary film texts.
Screen Australia - the diy.doco pages of the Screen Australia website are fantastic in explicitly demonstrating aspects of documentary filmmaking. This multimedia experience even does some of the teaching for you.
Australian Screen - the documentary pages of this site contain 420 profiles of a range of documentary titles, many with video extracts and teachers notes. Historic and contemporary documentaries are available. This is an excellent way to compare the documentary film techniques over time, as well as varying documentary styles and representations of reality.