Just head to Radio shack and get certian resistor (can't remember which one, sure its on miata.net someplace) and plug the ends into the now open connector in the wiring harness after removing the air bag. Think a set of several resistors costs ~$2.
Another note, AJ simply just unplugged his from the steering wheel and after a couple years with the resistors my air bag light came on. So as AJ told me to do one night, I just removed the resistors and no air bag light or buzzing noises! I don't care why but it works!
90 MX5 281k miles! - euro spec, Porsche Riviera Blue w/black hardtop, 97 motor swap, vintage Borbet rims, GC, FM shock hats/frame rails/rear sub-brace, AGX, sway bar, stb, Fidanza/ACT combo, EBC Yellows
92 COMMA SM - new paint coming soon...