Yes, this information is available in many different places and I’m sure we’ve all used many of them in the past. The only problem I’ve seen is that many of them are all proprietary sources that aren’t suitable for Free use. (I’m referring to teaching/coursework type of material).
There are a couple of wikibooks, but the structure didn’t seem very good at first glance.
I think the new thing would primarily be the GFDL/CC-BY(-SA) licensing and the ability to focus the work/writing around Free Software primarily. I think we’ve got a very talented group of people here, and their guidance/input also allows us to attach their name to the efforts. Hopefully this can help us to get more exposure for Free Software and the folks using it to the wider world!
As a mental exercise, I think it would be awesome from an outreach perspective to be able to answer questions from new photographers by pointing them to solid documentation that was Free and could hopefully begin to serve as a reference for others to point to as well.
I’d like to replace links to http://www.cambridgeincolour.com/ with a Free option!
I’d like to produce something that could conceivably be used by a photography teacher as part of their coursework (without licensing concerns) - better to expose people early to Free Software (as a side note, this is a common tactic of companies like Autodesk - cheap/free educational versions so students start thinking it’s an essential standard - I’d like to use the same tactic, but for better reasons).