A local foundation here in Florida, USA has developed a set of "Ten Keys to Civility". These are a perfect set of guiding principles for the project manager. Click here to view their website and find out more.
TEN KEYS TO CIVLITIY
Respect Others - Honor other people and their opinions, especially in the midst of a disagreement.
Think Positively - Keep an open mind and assume others have good intentions.
Pay Attention - Be aware and attend to the world and the people around you.
Make a Difference - Get involved.
Speak Kindly - Choose not to spread or listen to gossip.
Say Thank You - Let others know they are appreciated.
Accepts Others - Our differences are what make us interesting.
Rediscover Silence - Keep noise to a minimum.
Listen - Focus on others in order to better understand their points of view.
Keep Your Cool - Accept life's challenges with grace.