To find it definitively:
1. Consult your owner's manual: This is the best source for your specific vehicle. It should have a diagram showing the location of the PCV valve.
2. Use a repair manual (Chilton's, Haynes, etc.): These manuals provide detailed diagrams and instructions for your specific year and model.
3. Online resources: Search for "2000 Pontiac Grand Prix GT 3.8L PCV valve location" on YouTube or a car repair forum. You might find videos or photos showing the location.
Because you're working on your car, remember to always disconnect the negative battery terminal before you begin any work. And be careful around hot engine parts.