To locate it precisely, you'll likely need to:
* Consult a repair manual: A Haynes or Chilton repair manual specific to your 2001 Oldsmobile Alero will have diagrams showing the exact location and often includes instructions for testing and replacement.
* Use an online parts diagram: Many online auto parts stores (like AutoZone, Advance Auto Parts, etc.) have searchable parts diagrams. Entering your vehicle's year, make, and model should show you a diagram of your transmission and the location of the neutral safety switch.
Without looking at your specific car, giving a more precise location is difficult, as even the placement on the same transmission can vary slightly by model year and assembly plant. The above methods are your best bet for finding it.