An Introduction to Artificial Intelligence
Subject:   Neural nets aren't all supervised
Date:   2005-10-23 17:15:46
From:   ptwobrussell
Response to: Neural nets aren't all supervised

Just checked and there's a tiny overview of SOMs on Wikipedia:

But you're right. There are tons of AI learning techniques out there and just about every one of them has about a dozen well known variations of one sort or another. I would again refer the interested reader to Mitchell's Machine Learning for some high-quality treatment of many of the fundamental ones.