The airbag module is located at the base of the centre consol towards the firewall.
Is accesable by removing the drivers-side (far side) foot rest to the left of the clutch (or brake pedal in an auto).
You also need to remove the panel on the passenger side (near side for those people outside of Australia).
Is held in place by 3x nuts using a 10mm socket or spanner. The plug from the wiring loom to the module is on the passenger side. Use a screw driver to push in the clip fastener and slide it towards the rear of the car, then you can un-plug the connection easily.