found this on Canonfire, and it seems pretty good...
Codex of Honor
A righteous warrior always observes the rules of honorable warfare. The tenets of honor and chivalry are to be upheld even in the face of enemies that do not grant the same respects. Never strike a helpless opponent or one who is down and unable to defend himself.
Service to ones fellow man is the highest service one can undertake.
Law and justice are the cornerstones of a righteous society. Never subvert the rule of law in the name of expediency or put oneself above righteous authority.
Relentlessly pursue evil and destroy it, but never let the desire to smite the evils of the world take one outside the rule of law and justice. The ends do not justify the means.
Lethal force is not always the best option for dealing with evil. Do not let wrath cloud ones mind to other options that may lead to greater good.
Show the power and righteousness of Heironeous in every action and word. A righteous warrior can fight evil by providing an example of courage and good to all those who know him. Changing the hearts of men by example is one of the noblest ways to spread justice and law.
Be careful of who one associates with, the subtle influence of less righteous companions has been the downfall of many a noble warrior. A righteous warrior never associates with those he knows to be of questionable character.
Treachery and deceit are the tools of Hextor. Avoid them at all costs. Better to die a thousand deaths in the name of truth than to live by lying.
Beware the lure of riches and worldly possessions. The desire to acquire wealth and personal power will blunt the edge of a righteous warrior and cause him to center his attentions on things that do not spread law and justice, or show the power and humility of a knight of Heironeous. A knight who tithes half of his wealth to the church is blunting the lure of gold.
http://www.canonfire.com/html/modules.php?name=News&file=article&sid=307