To be sure, you should:
1. Consult your owner's manual: This is the most reliable source for the location of all fluid checks.
2. Look for a reservoir with markings indicating "Power Steering Fluid" or a similar label. It might be capped.
3. Check online forums or repair manuals specific to your 2002 Grand Prix's engine type. A quick search like "2002 Pontiac Grand Prix 3.8L power steering fluid location" might yield helpful images.
Don't hesitate to use a flashlight to help you see clearly in the engine bay. Be careful not to touch any hot engine parts.