10 Core Netiquette Rules, excerpted from Netiquette by Virginia Shea
Rule 1: Remember the Human
Rule 2: Adhere to the same standards of behavior online that you follow in real life
Rule 3: Know where you are in cyberspace
Rule 4: Respect other people's time and bandwidth
Rule 5: Make yourself look good online
Rule 6: Share expert knowledge
Rule 7: Help keep flame wars under control
Rule 8: Respect other people's privacy
Rule 9: Don't abuse your power
Rule 10: Be forgiving of other people's mistakes
For more details, go to The Core Rules of Netiquette
See also
"Netiquette" in Online Courses, Carleton University
Netiquette: Ground Rules for Online Discussions, Colorado State University (includes link to Word .doc for student use)