Here is a '98 explorer steering wheel replacement guide: How to Remove stock steering wheel and install aftermarket wheel on 95-01 Explorers - Ford Explorer and Ranger Forums "Serious Explorations"®
Just as a heads up when you are working with an air bag, they store an electrical charge for a few minutes, disconnect the battery and work on something else for 5 minutes before going to remove the air bag.
Now for the legal stuff, check with your State DMV, most allow owners to disable or remove airbags, not shops though, only the owner of the vehicle can do that.
Which could be an issue IF you are making payments on the vehicle, you are the "registered" owner, not the "legal" owner, so heads up.
Insurance is the touchy subject, your insurance payment for a vehicle is based on possible claims and the $$ amount at risk by the insurance company.
By removing the air bag the insurance company's possible $$ at risk could be higher, so without being informed of this change in "safety equipment" they could disallow injury claims in the event of an accident.