Well assuming its the 3.4L V6 its located on the pass side of the block(engine front) under the power steering pump.
So you would need to remove the pump to access it. Usulay pretty stuck in there, you might need to spray some penitrating fluid around it to loosen it up. It just pulls out after you remove the 1 8mm bolt and unplug the wire harness.
You'll be able to drive it untill it decides to give very inacurate readings on timing, you'll probly also see your MPG and performance drop.
Thier are some helpfull threads in the
N body Tips and Maintenance section that will help you remove the power steering pump and I have a pic or two of the sensor in the block if you need.
