toofanx's Journal: Unix History

This guy has made a Unix Family History Page. Quoting:

This is a simplified diagram of unix history. There are numerous derivative systems not listed in this chart, maybe 10 times more! In the recent past, many electronic companies had their own unix releases. This diagram is only the tip of an iceberg, with a penguin on it ;-).

It is a very well written web page, with a lot of very informative links.