They can check for this code at the dealer and maybe some auto parts supply stores. If it is an O2 sensor, it could be very expensive if done at the dealer - $150 just for the part in some cases!!

If you need to change one or both I'd take it to an independent shop (reputable): They might be able to give you a better price. While you're at it, go ahead and change plugs, rotor, cap, distributor, plug wires. I did and the car ran much better (better mileage, too). Also check for any vacuum leaks that might be causing the 02 sensor to fail. There's a hose near the manifold (looks like an elbow) that goes bad over time. Since it's in the shop anyway, go ahead and have minor stuff fixed - like the thermostat if it's never been done and flush the transmission fluid.

Good luck