It turns out Valve's Employee Handbook somehow leaked onto the internet, and its a great read. It really gives some good insight as to how the company works.
I find the "no management" structure really weird, but it must work for them, considering the many great games they have shipped.
So anyways, if you want to know more about Valve, you should give it a read. (also a Half-Life 3 tease inside, see if you can find it)