no. a forum is more organized. we're making it into an ebook, not a wiki. we already have a gimp wiki, and it doesnt really help. the ebook will be more organized and completely made by the community for all to view. right now we're just deciding what we think we should have as topics in the book, and then I will assign who is writing what. once everyone's written what they want, i and a select few will edit, correct, etc and i will put together the book.
Yep, GAP will do well. A lot of people have been asking about GAP. We should probably include how to install, set up, use, etc. As far as tutorials go, we won't have any. They only ones we'll have will be with the explanations of everything. As I said before, I might think about starting an advanced book after this one, if it turns out good. But hey, I like the idea of making a "Best of Gimp Tutorials" book. The only thing is I don't want to do that yet, as Gimp 2.5 and 2.6 will be released shortly, and I'd like to wait until after those are released before anything like that is made.