Skill rolls are made with a d20. Skill rolls are made to meet a Target Number (TN). A skill roll adds in one attribute which is noted in the skill's description. You do not automatically fail on a roll of 1, but you also do not automatically succeed on a roll of 20. Anyone may use any skill, though certain uses require you to be trained in the skill (Via the Skill Training feat).
Skill List:
Acrobatics
Athletics
Craft (Alchemy, Animal, Art, Engineering, Metal, Plant, or Stone)
Deception
Endurance
Gather Information
Heal
Initiative
Insight
Lore (Arcana, Bureaucracy, History, Nature, Planar, Religion, or Tactics)
Perception
Persuasion
Pilot
Ride
Spellcraft
Stealth
Survival
Thievery