Organized and editted by Raph Koster, designer of Ultima Online and a lot of other MUDs it seems, these are culminations of thoughts by a MUD developers. Some of these won't be useful at all as they are meant to be applied to massively multiplayer games, but I found them intriguing and some of them are very applicable to the smaller scale direct RPGs that we run here.
Most of these involve the philosophy of successful Game Mastering but there are also a few that are direct "Do's, Do Not's" that are helpful for the beginner GM.
http://www.legendmud.org/raph/gaming/laws.html
Fearless Leader