Go to the search there at the top and look up posts by author. Put in "green soap". She recently had a thread about all her experiments with natural colorants and she did quite a lot. It's a great thread.
I figured I would just go and look. Here's the link.
There are many discussions about using natural colorants in the CP section. Also, if you check out agriffin's blog, she's written about using natural colorants. http://www.lovinsoap.com/
As for scenting, I don't know how well anything might hold up through saponification that isn't concentrated. But there might be info about it on the forum that I haven't seen.