See this article on thewavelength.net...
http://articles.thewavelength.net/218/
...also read these...
http://articles.thewavelength.net/517/
http://articles.thewavelength.net/382/
And yes, I will probably be making a bot for Half-Life2 once the game and Half-Life2 SDK are released. I haven't decided whether it will be open source or not yet.
botman