Gasmizer, its really easy. you will need a portable light or small flash light, maybe a pad kneel on... bare with me...
open the drivers door all the way. (well I'm assuming you have a left hand drive) now kneel in the corner and look BEHIND the gas pedal toward the passengers side of the foot well. there you will see a long 10-12 inch by 2 inch wide hinged door. it will come off by pushing on the two tabs closest to the fire wall, and swing toward you. remove the door and you will see the cabin air filter there. you will need something like a small flat head screw driver to pry it out (not too difficult) Make sure that you notice that air flow arrows indicate flow toward the smarts shifter =>..
on 451s dot com we have photos of the whole process if I lost you with my description.