I have a National Audubon Society guidebook myself, and while it has several hundred species and nice color plates,
books are a relic of the last millennium. In this modern age, the Internet is our guidebook, either you post here and some amateur mycologist will give you a quick guess, which you can follow up with a Wiki search, or you go digging through sites like
Tom Volk's fungi webpage or
mushroomexpert.com.
I haven't found any regional guides for the Southeast, but then again, on-line is where I do most of my mycological research.