Ok...here we go. Take notes:
Disconnect the negative terminal from the battery, and make sure you TIE it out of the way. You don't want it moving back towards the battery. Remove the driver'* side hush panel underneath the column, and locate the connector with all the yellow wires and markings. It should be marked airbag circuit. Disconnect it WITH YOUR HEAD UNDERNEATH THE COLUMN....just in case
Now you can get your handy dandy torx bits out and remove the screws (four of them) from the dash side of the back of the steering wheel. The airbag assembly and switches (which are attached to it) will now move. Very gently disconnect the airbag connector and horn wire. You now have the 'airbag of death' in your hands.
Getting the switches out is now a no-brainer. If your switches aren't totally shot, I'd disassemble them and lubricate the little gray rubber thingies with a light silicone grease. Don't use a petroleum-based lube. If your switches are way beyond this, you'll have to replace the pods. They come as a set.
For 1992, the part number is 16141452 at $137.07 US (almost 200 from dealer)
For 93-95 it'* 16179632 at $104.73
For 96-99 you need both 16191172 and 16191172 at $64.76 each.
All prices are from www.gmpartsdirect.com
I don't suggest wrecker parts on these, as the cars generally sit in the heat, and degrade even faster than ours.