setskill "Skill" [,Value] [,"Name"]

Creates or changes a skill. They are displayed in your character menu and are like variables.
The value is 0 by default. "Skill" is the internal name for you skill. It will automatically be the visible name for your skill if you do not enter a "Name" value. If you enter a name value then this value will be displayed. Enter "" as name if you want to have a skill which is not visible in the character menu.
A click on a skill in the char menu creates a global even called skill_XXXXX while XXXXX is the internal name of the skills (spaces are replaced with _ there)